Higher blood nicotine concentrations following smokeless tobacco (pituri) and cigarette use linked to adverse pregnancy outcomes for central Australian Aboriginal pregnancies

doi:10.21203/rs.3.rs-1448071/v1

Download PDF

Research Article

Higher blood nicotine concentrations following smokeless tobacco (pituri) and cigarette use linked to adverse pregnancy outcomes for central Australian Aboriginal pregnancies

https://doi.org/10.21203/rs.3.rs-1448071/v1

This work is licensed under a CC BY 4.0 License

You are reading this latest preprint version

Background: In central Australia, Aboriginal women use wild tobacco plants, Nicotiana spp. (locally known as pituri) as a chewed smokeless tobacco, with this use continuing throughout pregnancy and lactation. Our aim was to describe the biological concentrations of nicotine and metabolites in samples from mothers and neonates and examine the relationships to maternal self-reported tobacco use, maternal and neonatal outcomes.

Methods: Central Australian Aboriginal mothers (and their neonates) who planned to birth at the Alice Springs Hospital (Northern Territory, Australia) provided biological samples: maternal blood, arterial and venous cord blood, amniotic fluid, maternal and neonatal urine, and breast milk. These were analysed for concentrations of nicotine and five metabolites.

Results: A sample of 73 women were enrolled who self-reported: no-tobacco use (n=31), tobacco chewing (n=19), or smoking (n=23). Not all biological samples were obtained from all mothers and neonates. In those where samples were available, higher total concentrations of nicotine and metabolites were found in the maternal plasma, urine, breast milk, cord bloods and Day 1 neonatal urine of chewers compared with smokers and no-tobacco users. Tobacco-exposed mothers (chewers and smokers) with elevated blood glucose had higher nicotine and metabolite concentrations than tobacco-exposed mothers without elevated glucose, and this was associated with increased neonatal birthweight. Neonates exposed to higher maternal nicotine levels were more likely to be admitted to Special Care Nursery. By Day 3, urinary concentrations in tobacco-exposed neonates had reduced from Day 1, although these remained higher than concentrations from neonates in the no-tobacco group.

Conclusions: This research provides the first evidence that maternal pituri chewing results in high nicotine concentrations in both the mother and neonate and that exposure may be associated with adverse maternal and neonatal outcomes similar to those from smoked tobacco use in pregnancy. Screening for the use of a broader range of tobacco and nicotine products during pregnancy would provide a more inclusive assessment and contribute to a more accurate determination of tobacco exposure. This knowledge will better inform maternal and foetal care, and direct attention to targeted cessation strategies that are appropriate to the tobacco and nicotine use profile of the population.

Note to readers: In this research, the central Australian Aboriginal women chose the term ‘Aboriginal’ to refer to themselves, and ‘Indigenous’ to refer to the broader group of Australian First Peoples. That choice has been maintained in the reporting of the research findings.

pregnancy

maternal

neonatal

smoking

smokeless tobacco

pituri

tobacco

nicotine

central Australia

Australian Aboriginal and Torres Strait Islander people

In maternal non-Westernised populations, the use of smokeless tobacco (SLT), rather than smoking, is the normalised tobacco use behaviour [1]. Data from 140 countries shows that there are an estimated 90 million women > 15 years of age who use SLT products [1, 2]. The term SLT describes tobacco products that, rather than being burnt, are used as solids, pastes or powders in the nasal and oral cavities or on the skin [1]. Frequently used products include plug, snuff, toombak, paan, mishri, dissolvable tobacco lozenges and strips.

Nicotine is the principal pharmacologically active and addictive compound in tobacco. The use of SLT enables the extraction and absorption of nicotine and other compounds from the tobacco plant without exposure to the products of tobacco combustion associated with cigarette use [3]. In Australia, Aboriginal populations in the central regions use wild tobacco plants (Nicotiana spp.), known as pituri, as SLT [4]. The plants are dried, then combined with wood ash from specific trees, before being chewed into a mass (known as a quid) and retained behind the lip in the buccal space for extended durations. Analysis of dry leaf Nicotiana spp. preferred for use as pituri has demonstrated nicotine content as high as 11 mg/g [5]. The addition of the highly alkaline wood ash to the quid raises its pH [6], which increases the proportion of unprotonated (free-base) nicotine and enables increased nicotine absorption through the oral mucosa [7]. If the wet quid is removed from the lip, it is commonly placed behind the ear for later use, which creates a potential transdermal nicotine administration route [8]. The habitual use of pituri is established in early life and continues throughout pregnancy and lactation [9].

Nicotine is an agonist at nicotinic acetylcholine receptors (nAChRs) except at two nAChR subunits where is acts as an antagonist [3]. Nicotine produces wide-ranging generic, reproductive and pregnancy-specific biphasic responses, transitioning from initial simulation to depression in a dose-dependent and cumulative manner based on a range of individual factors including genetics, age, gender and pregnancy [3]. Nicotine transits across the placenta, becoming concentrated in the placenta and the foetus as demonstrated by higher ratios in the umbilical venous and arterial cord bloods than in maternal serum [10] and nAChR binding in the developing and immature foetus [11].

Nicotine has a half-life of about two hours and is metabolised via the CYP2A6 pathway primarily in the liver, with the brain, kidneys and lungs providing minor sites [12]. This short half-life produces large nicotine serum plasma fluctuations. Cotinine, the main nicotine metabolite [13], has a half-life of approximately 17 hours and serum concentrations 10-fold higher than nicotine, providing a more stable biomarker of nicotine exposure [14]. Other major metabolites include 3’-hydroxycotinine, nornicotine, nicotine glucuronide and nicotine-N-oxide [15]. Nicotine and its metabolites are excreted by the kidneys with the rate being dependent upon urinary pH. During pregnancy, there is a significant induction of CYP2A6 activity that increases nicotine plasma clearance by 60% and cotinine clearance by 140% resulting in an almost 50% reduction in cotinine half-life, down to 9 hours from 17 hours [16]. Clinically, these changes are important, as reduction in nicotine and cotinine concentrations in late pregnancy compared with pre-pregnancy or early pregnancy may not necessarily reflect a decrease in nicotine exposure, but rather the more rapid metabolism [17]. The foetus and neonate have immature CYP2A6 activity, which decreases their ability to metabolise nicotine, resulting in longer plasma nicotine half-life relative to adults (11.2 hours compared to 2 hours), whereas cotinine elimination is similar to that of adults (16.3 hours compared with 17 hours) [18].

Extensive research over the past 60 years has demonstrated that maternal smoking, SLT use, and/or maternal exposure to second-hand cigarette smoke have adverse maternal and neonatal outcomes [19–23]. For the mother, these outcomes may include delayed conception, increased risk of miscarriage, ectopic pregnancy and elevated glucose [24–28]. At the foetal macro level, nicotine exposure is associated with reduced gestational length (preterm birth < 37 weeks gestation), low birthweight (LBW) and malformation [29]. Gestation length and birthweight are key markers of foetal health and are significantly influenced by the presence of elevated maternal glucose. Furthermore, the transition from a high glucose intrauterine environment to independent glucose control following birth can be challenging for neonates exposed to elevated maternal glucose [30–32] and increases the likelihood of neonatal admission to Special Care Nursery (SCN) [33, 34]. At the foetal micro level, the nicotine has a teratogenic impact on neural nAChRs and neural physiology, increasing the risk for stillbirth, sudden infant death syndrome (SIDS) and Sudden Unexplained Death in Infancy (SUDI) for exposed offspring compared with non-exposed offspring [35–38].

Based on the evidence of nicotine exposure and adverse foetal impacts, nicotine is internationally classed as a Category D drug in pregnancy [39, 40]. The Australian Category D definition is “drugs which have caused, are suspected to have caused or may be expected to cause, an increased incidence of human foetal malformations or irreversible damage” [41]. The immediate adverse foetal and neonatal outcomes (i.e., pre-term birth, lower birthweight, stillbirth, SIDS) tend to overshadow and draw attention away from the adverse impact of in-utero nicotine exposure on foetal programming and the consequences to the offspring of lifelong increased risks for acute and chronic illness and disease including childhood obesity, early onset cardiovascular and respiratory disease and cognitive and behavioural barriers (attention-deficit/hyperactivity disorder (ADHD) and learning challenges) [42–46].

In Australia, maternal, pregnancy, birthing and neonatal information is gathered as part of the National Perinatal Data Collection [47]. For that collection, only maternal self-reported cigarette use is captured and reported twice; once before 20 weeks gestation, and once after 20 weeks gestation. That data shows the smoking rate for Indigenous mothers is 44% compared with 12% for non-Indigenous mothers [48]. The self-reported smoking rate for Northern Territory (NT) Indigenous mothers in the first 20 weeks of pregnancy is 52%, with a much lower rate of 30% reported for Indigenous women in the Alice Springs rural district [49]. This difference across the NT is surmised to be related to the traditional practice of chewing of tobacco (pituri) in the central region compared with the use of cigarettes in the north, commonly referred to as the Top End [50]. Maternal smoking and pregnancy outcomes from the Australian Mothers and Babies Report [51] and NT Mothers and Babies Report [52] identify that live-born babies born to Indigenous mothers who smoked were 18% more likely to be born pre-term compared with 12% of those born to non-Indigenous mothers who smoked. The data indicates that Indigenous maternal smoking accounts for 47% of low-birthweight babies compared to 12% for non-Indigenous babies [53].

Clinical findings from the cohort of 73 Central Australian Aboriginal mother-neonate pairs enrolled in this research [54, 55] indicate that the most clinically and statistically significant maternal outcomes were differences in hypertension and anaemia across the groups, and a higher rate of elevated maternal glucose in pituri chewing mothers (48%) compared with smoking mothers (22%) and no-tobacco using mothers (16%). The presence of elevated maternal glucose was associated with the birthweights of neonates, although the cohort neonate birthweight mean (3348 g) showed no difference between the nicotine user (or not) groups. When stratified for elevated maternal glucose, the neonates born to pituri chewers had the lowest mean birthweight (2906 g) compared to the neonates of the no-tobacco group (3242 g) and smokers (3398 g). Additionally, the neonates of chewers had lower APGAR scores and higher admission rates to SCN compared with the neonates of smokers (44% v 23%). In addition, there were differences in gender, and placental weight and diameter between the three exposure groups. The research question addressed in this paper is ‘what are the biochemical concentrations of nicotine and metabolites (NM) in a range of maternal and neonatal biological samples from mothers with differing levels of self-reported tobacco use?’. The aim is to describe the NM concentrations from maternal blood, maternal and neonatal urine, breast milk and amniotic fluid and examine any relationships with self-reported maternal tobacco exposure, and maternal and neonatal outcomes.

Sampling frame, sample size, inclusion and exclusion criteria.

The protocol for the research has been published elsewhere [56]. Briefly, all pregnant central Australian Aboriginal women, ≥ 18 years of age, with a singleton pregnancy, ≥ 28 weeks gestation, and who planned to birth at the Alice Springs Hospital, NT, Australia were conveniently offered enrolment in the research. Based on the observed rates of pituri use (33%), smoking (33%) and no-tobacco use (33%), and the sample size from a similar project with Alaskan Native women [57], 20 mother-neonate pairs in each tobacco exposure group was required to answer the research question and provide data to inform the development of further research questions.

The health of central Australian Aboriginal mothers is challenged by a range of circumstances and conditions which are known predictors for adverse pregnancy and neonatal outcomes, including low levels of education and access to antenatal care, high levels of unemployment, poor housing and nutrition, high rates of urinary tract and sexually transmitted infections, anaemia, diabetes and renal disease [58–60]. Given the endemic occurrence of these in the population, these were not used as exclusion criteria for eligibility. The only maternal exclusion criterion was self-reported dual pituri and cigarette use; excluded due to the lack of research resources to enable the distinction between nicotine biochemical concentrations absorbed through the maternal respiratory tract vs. through the maternal oral and transdermal routes [61].

Participant characteristics, tobacco use and biological data collection tools.

Three data collection strategies were used to address the research question, with the data being collected by Aboriginal Health Workers, Aboriginal Liaison Officers and midwives. The first data collection followed participant enrolment and comprised a semi-structured demographic and tobacco-use interview. The second strategy was the extraction of the pregnancy, labour and birth information from CARESYS® (the NT electronic medical record system). Any CARESYS® report of diabetes (pre-gestational or gestational) was categorized as “elevated glucose” and likewise any report of hypertension (pre-gestational or gestational) as “elevated blood pressure” for the analysis in this research. The third strategy was the collection of biological samples from the mother, placenta and neonate to measure the maternal, foetal and neonatal exposure and excretion of NM (Table 1).

Table 1. Biological samples collected for nicotine and metabolite (NM) measurement and their rationale

for collection in response to the research question.

Biological sample	Rationale for collection
Maternal venous blood	- indicates recency of maternal nicotine exposure [62]
Umbilical vein cord blood	- indicates nicotine placental transfer (and foetal exposure) from the maternal circulatory system
Umbilical artery cord blood	-indicates foetal nicotine excretion via the circulatory system (and return to the mother)
Amniotic fluid	- demonstrates foetal nicotine exposure directly through the amniotic membrane, and foetal nicotine excretion via the foetal kidneys and lungs [11, 63–65]
Maternal urine	- indicates maternal nicotine excretion via urinary system [3]
Neonatal urine	- comparison of Day 1 and Day 3 urine with umbilical vein and umbilical artery cord bloods may demonstrate neonatal nicotine absorption, metabolism and excretion [18]
Colostrum and/or breast milk	- indicates nicotine excretion and possible route of post-birth nicotine exposure [66, 67]

Biological data collection, storage and analysis

Biological samples were collected as they became available and when sampling did not impact clinical care. Maternal plasma and non-sterile urine were concurrently collected with other plasma and urine collections so as to minimise participant discomfort. A sample of amniotic fluid that was not visibly contaminated with maternal blood or meconium was obtained at caesarean section (CS). Cord bloods were collected as per standard umbilical cord blood collection procedures, following the complete expulsion of the placenta from the uterus and the complete separation of the placenta from the neonate. Neonatal urine collection bags were placed on the neonate after birth and again on Day 3, and urine was collected when available and if visibly uncontaminated with meconium. Mothers were encouraged to collect their breast milk when that became available. Under the counsel of the Aboriginal advisory group, no biological samples were collected from the placentas or neonates who were stillborn.

Participant samples were frozen (-80^oC) until their transport for analysis. The samples were batch analysed for nicotine, cotinine, 3’-OH-cotinine, nornicotine, nicotine-N-oxide and nicotine glucuronide following the methodology contained in Additional file 1. The analysis was conducted by one scientist (BM) who was blinded to the self-reported tobacco use status of participants.

Data analysis

Maternal self-reported tobacco use at initial enrolment interview was used to categorise participants into one of the three tobacco use groups: (a) no-tobacco user, (b) chewer, or (c) smoker. The concentration of nicotine, cotinine, 3’-hydroxycotinine, nornicotine, nicotine-N-oxide and nicotine glucuronide in each sample was summed and reported as a per sample total for data analysis [68]. NM concentrations were compared with maternal, birthing and neonatal variables of clinical interest; elevated maternal glucose, hypertension, anaemia, placenta characteristics, and neonatal gender, birthweight, gestational age, APGAR score and admission to SCN [54, 55].

Data from the interview, CARESYS® files and biochemical results were de-identified and imported into SPSS® (IBM® SPSS® Statistics 20) and Stata 17 (Statacorp, Texas) for the analyses. Descriptive statistics including frequencies, means and 95% confidence intervals (CI) were calculated, with differences in means tested using students t-test where appropriate. Box and whisker graphs were used to summarise median, interquartile ranges and outlier data according to tobacco-use groups. Where individual outcome results were in conflict with their self-reported tobacco use status, these were retained and included in the analysis of the self-reported tobacco-use group.

Ethical considerations

The research design and methodology were informed and overseen by a regional Aboriginal Women’s Council. Ethical approval was obtained from the Central Australian (#2010.06.04) and The University of Queensland Human Research Ethics Committees (#2010000548 and #2015001429). All participants provided written informed consent prior to enrolling in the research and all methods were performed in accordance with the guidelines and regulations of the National Statement for the Ethical Conduct in Human Research [69].

Nicotine and metabolite concentrations

A total of 73 mothers and 73 neonates participated in the research. Two neonates were stillborn at 40 weeks gestation; their mother’s pregnancy and their birth data are reported, but no biological samples were collected from these neonates. For the other 144 participants, it was not possible to collect or analyse all samples for every participant because the sample was either declined by the participant, or was required for clinical care, or was contaminated with other biological fluid, or was inadequately labelled, or there was an inadequate sample volume for analysis. Additionally, six mothers birthed at other hospitals or before arrival at Alice Springs Hospital. The following were analysed: 61 maternal blood, 37 cord blood, 6 amniotic fluid, 59 maternal urine, 32 neonatal urine Day 1, 20 neonatal urine Day 3, and 39 breast milk samples. For the umbilical cord blood collections, almost half (11/37) were insufficiently labelled to clearly identify the sample by vessel of origin (artery or vein). Therefore, the unidentified cord blood results have been separately included in this report, with the mean value of the unlabelled samples reported if more than one sample was available for each participant.

The no-tobacco group provided the control for this research showing NM mean concentrations of 91 ng/mL in the maternal blood and 74 ng/mL in their urine, and similar values in the cord blood and neonate urine (Table 2). This group included one outlier with an exceedingly high blood NM concentration indicating very recent tobacco use even though she self-identified as a no-tobacco user. (Fig. 1). The range of NM concentrations between individuals in both the chewer and smoker groups varied widely (Table 2), perhaps indicative of differences in recency of exposure and individual nicotine kinetics (Fig. 1). Even with this wide range, statistically significant differences between no-tobacco and chewers and smoker groups are evident.

As expected, tobacco chewers and smokers had considerably higher mean NM values than the no-tobacco group concentrations (Table 2), with maternal blood NM concentrations about double (212 ng/mL chewers; 174 ng/mL smokers) and urine NM concentrations approximately 10 times greater (829 ng/mL chewers; 649 ng/mL smokers). For mothers with both blood and urine available (n = 55) the mean maternal urine (467 ng/mL, 95% CI 318–616) far exceeded the mean maternal blood concentration (149 ng/mL, 95% CI 94–203, p < 0.005).

The chewer group had the highest mean NM concentrations in most of the biological fluids. The mean value for the amniotic fluid from chewers was the highest of all biological fluids (1210 ng/mL), followed by their arterial cord blood (1195 ng/mL), and maternal urine (829 ng/mL).

Table 2

Total nicotine and metabolite concentration (NM, ng/mL) mean and 95% confidence interval for maternal and neonatal biological fluids according to maternal self-reported tobacco use (n = 73).

	No-tobacco n = 31			Chewer n = 19				Smoker n = 23
	n	NM mean	NM 95% CI		n	NM mean	NM 95% CI	n	NM mean		NM 95% CI
Maternal blood, n = 61	28	91	7–176		15	212	104–321	18	174	116–231
Cord blood¹, n = 37	15	74	37–111		10	734	327–1141	12	430	196–664
Vein cord blood, n = 26	12	89	16–163		4	597	-56–1250	10	541	226–855
Artery cord blood, n = 18	7	87	15–164		3	1195	-1058–3447	8	373	96–651
Unknown cord blood vessel², n = 11	3	38	26–51		6	721	125–1318	2	126	-863–1115
Amniotic fluid, n = 6	0	-	-		4	1210	598–1822	2	806	-1393–3004
Maternal urine, n = 59	26	74	54–93		16	829	482– 1176	17	649	400–899
Neonatal urine Day 1, n = 32	16	101	82–120		8	234	90–378	8	184	104–265
Neonatal urine Day 3, n = 20	13	78	61–95		4	118	92–144	3	153	81 − 224
Breast milk, n = 39	19	10	3–17		10	54	17–91	10	11	4–18
¹Cord blood value is the mean value of all cord blood samples per participant. All participants who had an arterial cord collection also had a venous cord collected, some participants only had venous cord.
²18 cord blood samples from 11 participants were not labelled with source vessel (i.e., arterial or venous). If more than 1 sample from each participant, then mean value of samples was used.

Transfer of NM between the maternal and foetal circulation at the time of birthing is reported by umbilical cord blood. For the 30 participants for whom both cord blood and maternal blood samples were analysed, NM concentrations were higher in cord blood than in their maternal blood (mean cord blood 410 ng/mL, 95% CI 232–588; maternal blood 116 ng/mL, 95% CI 75–157; p = < 0.005). Notably, NM concentration in cord blood was more than double maternal blood for the smokers (430 ng/mL vs 174 ng/mL), and more than triple for the chewers (734 ng/mL vs 212 ng/mL).

Amniotic fluid is a further indicator of foetal exposure to nicotine. Amniotic fluid uncontaminated with maternal blood or meconium was very difficult to acquire at the time of vaginal birth. The samples that were obtained (n = 6) were from caesarean section births. Consequently, with so few samples it is not possible to make comparisons, however, the six tobacco users mean NM concentration in amniotic fluid was significantly higher than their maternal blood NM concentrations (amniotic fluid 1075 ng/mL, 95% CI 677–1474; maternal blood 252 ng/mL, 95% CI 81–422, p < 0.005).

Neonatal excretion of NM was measured in neonatal urine at Day 1 and Day 3 with the chewers and smokers having higher Day 1 concentrations than the no tobacco group (234 ng/mL, 95% CI 90–378; 184 ng/mL 95% CI 104–265; 101 ng/mL 95% CI 82–120 respectively). Day 3 results show declines in each group (chewers 118 ng/mL, 95% CI 92–142; smokers 153 ng/mL 95% CI 81–224; no-tobacco group 78 ng/mL 95% CI 61–95). Neonates from the three groups with both Day 1 and Day 3 results (n = 15) showed a decline in NM concentration over that period of time (Day 1 neonatal urine 152 ng/mL, 95% CI 77–227, Day 3 neonatal urine 93 ng/mL, 95% CI 71–116, p = 0.07). From neonates with both urine and cord blood samples, the NM urine levels were lower than cord blood concentrations (n = 17; Day 1 neonatal urine 192 ng/mL, 95% CI 119–264, all cord blood 479 ng/mL, 95% CI 197–762, p = 0.02).

The continued exposure of neonates to nicotine via breastfeeding was also considered (Table 2). Concentrations were lower in the breast milk than all other biological fluids, however the highest readings were recorded in chewers (54 ng/mL, 95% CI 17–91) followed by the smokers (11 ng/mL, 95% CI 4–18) and non-tobacco users (10 ng/mL, 95% CI 3–17).

Relationship of nicotine concentrations with maternal outcomes

In the cohort of 61 mothers with maternal blood collections, 33% of tobacco users had elevated maternal glucose (47% of chewers and 22% of smokers) compared to 18% of the no-tobacco group (Table 3). Mean maternal blood NM for chewers with elevated blood glucose was almost double chewers without elevated glucose (288 ng/mL compared with 146 ng/mL). Similarly, maternal blood NM levels for smokers with elevated blood glucose (253 ng/mL) was higher than smokers without elevated glucose (151 ng/mL).

Participants with anaemia tended to have lower NM concentrations (chewers 137 ng/mL, smoker 141 ng/mL, no-tobacco users 63 ng/mL) compared with those without anaemia (chewers 218 ng/mL, smokers 183 ng/mL, no-tobacco users 102 ng/mL), though the number of participants with anaemia was low and variability was high (Table 3). The relationship between maternal hypertension and NM concentrations was inconsistent between groups (Table 3). Smokers with hypertension had lower mean NM (110 ng/mL) than smokers without hypertension (192 ng/mL) while the no-tobacco hypertensive group mean NM (206 ng/mL) was higher than those no-tobacco users without hypertension (53 ng/ml), although when data from one very high NM level (1190 ng/ml) in the no-tobacco group was omitted from analysis, the mean NM for the no-tobacco hypertensive group was 42 ng/mL. The single chewer with hypertension had a high maternal blood NM (291 ng/mL) compared to the mean for chewers without hypertension (207 ng/mL).

Relationship between maternal NM levels with neonatal and placental outcomes

The average birthweight for the 61 neonates was 3290g, with little difference between the three tobacco exposure groups (Table 3). The mean birthweight for male neonates were 510 and 630 g heavier than the female neonates of chewers and smokers respectively, but in the no-tobacco group males (3209 g) and females (3372 g) were very similar weights. Maternal blood NM levels were higher with male neonates (168 ng/mL) compared to females (121 ng/mL). Between groups, this trend was similar for the no-tobacco and chewing groups with slightly more males born (57% and 60% respectively) and higher maternal NM levels (male 128 ng/mL v female 43 ng/mL, and male 257ng/mL versus female 146 ng/mL respectively) compared with the smoking group who had fewer males than females born (43%) and mothers NM levels of 146 ng/mL for male and 192 ng/mL for female neonates.

In the chewers, neonates exposed to elevated glucose and higher maternal NM (288 ng/mL) weighed 1014 g more than the neonates of chewers who were not exposed to elevated glucose and lower maternal NM (146 ng/mL). This same trend existed for smokers only when a very small (900 g) pre-term 27-week gestation neonate was excluded from the elevated glucose group for analysis, in which case neonates from smokers exposed to elevated glucose weighed 472 g more than those not exposed (3869 g versus 3398 g).

Table 3

Maternal blood total nicotine and metabolite concentration (NM) according to maternal self-reported tobacco self-reported tobacco use (n = 61), and subdivided according to maternal, neonatal and placental characteristics, outcomes and complications. Data are the frequency, mean and 95% confidence interval for NM in mg/mL. Birthweight (g), placenta weight (g) and placenta size (cm x cm) are shown in italics.
	No-tobacco			Chewer			Smoker
	n	mean	95% CI	n	mean	95% CI	n	mean	95% CI
Maternal outcomes (n = 61)
Maternal blood NM, ng/mL	28	91	7–176	15	212	104–321	18	174	116–231
Elevated glucose
Yes n = 16	5	36	30–43	7	288	48–527	4	253	20–486
No n = 45	23	103	0–207	8	146	71–222	14	151	93–209
Hypertension
Yes n = 12	7	206	-196–608	1	291	-	4	110	24–196
No n = 49	21	53	39–67	14	207	91–323	14	192	120–263
Anaemia
Yes n = 13	8	63	30–96	1	137	-	4	141	-110–392
No n = 48	20	102	-18–223	14	218	101–334	14	183	122–245
Neonatal outcomes (n = 61)
Mean birthweight, g	28	3279	3051–3506	15	3253	2834–3673	18	3338	2828–3847
Gestation
< 37 weeks n = 7	3	443	-1166–2052	2	341	-2104–2786	2	130	-897–1156
≥ 37 weeks n = 54	25	49	36–62	13	193	79–306	16	179	116–243
Exposure to elevated glucose
Yes n = 16	5	36	30–43	7	288	48–527	4	253	20–486
mean birthweight, g	5	3466	2223–4709	7	3794	3287–4301	4	3127	734–5520
No n = 45	23	103	0–207	8	146	71–222	14	151	93–209
mean birthweight, g	23	3238	3030–3445	8	2780	2293–3267	14	3398	2871–3925
Gender
Male n = 32	16	128	-24–280	9	257	72–441	7	146	57–235
mean birthweight, g	16	3209	2931–3486	9	3457	2920–3995	7	3723	2857–4589
Females n = 29	12	43	28–57	6	146	67–225	11	192	105–278
mean birthweight, g	12	3372	2941–3802	6	2947	2111–3783	11	3093	2392–3793
Neonate admitted to SCN¹
Yes n = 22	11	155	-76–387	7	333	123–542	4	215	-72–501
No n = 39	17	50	33–67	8	107	46–169	14	162	106–218
APGAR at 5 minutes¹
< 7 n = 6	3	45	-17–106	2	431	-3260–4121	1	200	-
≥ 7 n = 53	24	99	1–198	13	179	91–267	16	170	104–235
Placental characteristics¹ (n = 40)
Maternal blood NM, ng/mL	21	103	-11–217	10	187	73–301	9	145	87–202
Placenta size, cm x cm	21	299	270–327	10	280	213–347	9	250	198–302
Placenta weight, g	21	572	524–620	10	488	376–599	9	667	268–1065
¹ Data for neonatal live births only (n = 59)

SCN admission was more frequent for neonates of chewers (47%) than smokers (22%) and no-tobacco-users (39%), and those admitted had higher maternal blood mean NM concentrations than those not admitted (no-tobacco 155 ng/mL vs. 50 ng/mL; chewers 333 ng/mL vs. 107 ng/mL; smokers 215 ng/mL vs. 162 ng/mL). Very few neonates had APGAR scores of < 7 at five minutes (Table 3), but for the chewers, those with scores < 7 had higher maternal blood NM concentrations than those with ≥ 7 scores (431 ng/mL versus 179 ng/mL).

Of the 61 births, 40 placentas were able to be examined (Table 3). There was a trend towards higher NM concentrations associated with smaller and lighter placentas. In the smoking group there was one extremely large placenta (weight was verified, 1960 g), that if omitted, brought the average placenta size and weight to 259 cm² and 505 g.

This paper reports the concentration of NM in a range of biological samples from prospectively and conveniently enrolled central Australian Aboriginal pregnant women at hospital for the birth of their baby; mothers self-reported their tobacco use as being chewers, smokers, or no-tobacco use. We also considered NM concentrations in relation to the maternal, birthing, placental and neonatal characteristics and outcomes previously described for these families within the overarching research [54, 55].

The population consisted of 58% self-reported tobacco users (SLT 26%, smokers 32%), however in the self-reported no-tobacco group, several high maternal NM concentrations were indicative of tobacco exposure. Re-categorisation of participants based on NM concentrations would have enabled a more robust statistical analysis including correlation and regression, however this re-categorisation was not conducted for the following reasons. Firstly, urinary cotinine levels (i.e., nicotine metabolism) is commonly used as a cut-off value to indicate tobacco use in pregnancy, yet the literature reports a wide range in cut-off values for example 250 ng/mL [70], 82 ng/mL [71], and 42 ng/mL [72]. Secondly, nicotine metabolism is highly individual and is influenced by previous exposure, recency of exposure prior to collection, tobacco formulation, diet and body weight. Importantly, evidence shows that following equivalent tobacco exposure, ethnically different populations have varied nicotine intake and cotinine clearance [73, 74] and specific genomic variations have been identified and contribute to the biological variation in NM findings in different populations [75]. As yet, genome research related to the metabolism of nicotine in pregnant Australian Aboriginal populations has not been conducted. Furthermore, there were dissimilarities in study designs and methods between this research and other studies including differences in laboratory techniques and analysis equipment. Given these issues it was considered premature to extensively compare nicotine absorption and clearance concentrations, and maternal and neonatal outcomes in this research cohort with wider findings. Lastly, the Australian maternity data collection is based on self-report, by retaining the self-reported categorisation, it is possible to compare the research findings with the National Perinatal Data Collection.

Maternal nicotine exposure and outcomes

In Australia, the National Perinatal Data Collection reports on mothers’ use of cigarettes twice during pregnancy and there is no opportunity to report SLT or nicotine containing products such as e-cigarettes, nicotine gum, patches, mists, tooth powder or lozenges. Accordingly, the pituri users’ outcomes in this research will have been recorded in the National Perinatal Data Collection as “no-tobacco use”, thus, incorrectly reporting the nicotine exposure outcomes for these Aboriginal and Torres Strait Islander mothers and babies at the local, territory, national and international level. Modifying the pregnancy health assessment and data collection tools to record the broader range and use of nicotine containing products will enable a more inclusive and discriminative assessment of their effects on contemporary Australian pregnancies and outcomes.

The Perinatal data reports the rate of smoking in pregnancy by Indigenous women across Australia is 44% [48], and the reported rate of smoking in the first 20 weeks of gestation is 52% across the NT. The reported rate of smoking for Indigenous women in the Alice Springs area is 30% [49] and comparable to the finding in this research of 32%. In this research, which captured SLT use as well as cigarette use, there were indications of higher mean concentrations of NM in the chewer group’s maternal blood, umbilical cord blood, amniotic fluid, neonatal urine Day 1 and breast milk in comparison with the smoker and no-tobacco use groups. Higher concentrations of NM in both tobacco user groups were aligned with several clinically important maternal differences, specifically as follows, in the rate of elevated glucose, hypertension and anaemia.

In general populations, smoking has been identified as a risk factor for the development of diabetes [76, 77], and while the development of impaired glucose regulation is a normal physiological change in pregnancy [78], both pre-pregnancy and maternal smoking increase the risk of gestational diabetes [26–28]. Globally, the rate of diabetes in pregnancy is higher in Indigenous populations [79] and there is also a higher use of tobacco in these populations [1]. At the Australian level, the incidence of gestation diabetes has increased from 5.2% in 2000–2001, to 9.3% in 2012–2013, to 15.1% in 2016–2017 [80]. In this research, the high maternal blood NM levels in the tobacco-exposed groups with elevated glucose, and the lower NM levels in the tobacco-exposed groups without elevated glucose suggests the involvement of nicotine in insulin resistance or glucose metabolism as opposed to a mechanism related to only the combustion of tobacco. The presence of elevated glucose impacts the mother during pregnancy as well as her longer-term health, with approximately 50% of affected mothers going on to develop diabetes within 10 years of first diagnosis of gestational diabetes [81].

While nicotine is a potent vasoconstrictor [3], counterintuitively smoking in pregnancy results in a dose-dependent decrease in hypertension [20, 82–84]. Our data for smokers supports this assertion, with fewer cases of elevated hypertension in the smokers than no-tobacco users. There is evidence of hypertension in smoking participants with lower mean maternal blood NM concentrations compared with an absence of hypertension in those with higher NM levels. Chewing tobacco was expected to follow the same trend [31] (i.e., higher NM and an absence of hypertension) and this was evidenced with only one chewer having a record of hypertension. This one participant had a very high NM (291 ng/mL). In the no-tobacco group, with the removal of the one high NM result (1190 ng/mL) from a participant with hypertension, the mean NM result was 42 ng/mL for those with hypertension, and 53 ng/mL in those without hypertension.

Maternal anaemia occurred less often in participants with higher mean NM concentrations compared with those with lower mean concentrations. These findings are contrary to the literature which shows that smoking and SLT use in pregnancy is associated with maternal anaemia [22, 85–87], however there may be endemic confounders in this population that explain this finding. In the geographical region, Hymenolepis nana (intestinal worms) are endemic, and anaemia is associated with approximately 18% of infections [88]. Nicotine exposure is a treatment for intestinal worms in humans and animals [89–91], and in this population, we hypothesise that exposure to nicotine from pituri chewing and smoking may decrease the worm burden in a dose-dependent manner and thereby decrease the resultant anaemia from this parasite.

Neonatal nicotine exposure and outcomes

Nicotine readily transits from the maternal circulation to the placenta and much has been written around the neonatal outcomes of in-utero exposure during pregnancy, birth and early infancy [92], however longer-term outcomes are being demonstrated including that in-utero nicotine exposure permanently impacts the foetal pancreas and results in a loss of beta cell mass, leading to a life-long increased risk of impaired glucose and insulin homeostasis, childhood and adult obesegenesis [93–96], and childhood [97] adult hypertension [98] and type 2 diabetes [99].

In this research, evidence of neonatal exposure to nicotine was demonstrated with NM concentrations in arterial and venous cord blood and amniotic fluid in those exposed to tobacco through smoking or chewing and notably, these concentrations were significantly higher than the maternal blood concentrations. The unlabelled cord blood values are comprised of a mixture of venous and arterial samples, so while it may appear that the arterial cord blood NM concentrations may be higher than venous cord blood from chewers (Table 2), these are based on only three participants for whom both labelled samples were available, and the relationship is reversed for the eight smokers for whom there were both cord blood samples.

As observed in this research through NM concentrations measured in urine, the neonate and the mother are able to excrete nicotine via the kidney [18, 100] and Day 1 NM urine concentration is a useful biomarker for nicotine exposure. Following birth and the discontinuation of the supply of nicotine via the placenta, neonatal urine from chewers and smokers declined in NM concentration from Day 1 to Day 3. Whilst this finding provides some reassurance of the neonatal ability to excrete the NM resulting from in-utero exposure, the mean concentrations in both the neonates of chewers and smokers did not equate to that of the neonates from the no-tobacco use group by Day 3. However, we were not able to take account of hydration status with these small volumes, so no inferences can be made.

There is potential for continued neonatal nicotine exposure following birth through breast milk [101]. NM concentration in breast milk from smokers was low and similar to the no-tobacco group (11 mg/mL) while breast milk of chewers was higher (54 ng/mL). Pituri can be used discretely, and continuously throughout the hospital stay which may account for these higher levels. It may also be associated with slower clearance from breast milk in chewers than smokers, as breast milk is clear of nicotine in smokers after four hours of abstinence, but is still present in snus (SLT) users’ after abstaining from tobacco use for 11 hours [97].

We anticipated higher rates of SCN admission for the smoker group than the no-tobacco group [102], but in fact the opposite was true, with less smokers compared to no-tobacco neonates treated in SCN. Pituri chewers were most likely to be admitted and this was associated with high mean maternal blood NM, indeed, all mothers whose neonates were admitted to SCN had higher blood NM than mothers of non-admitted neonates.

Literature from smoked tobacco research indicates a reduction in male newborns in the presence of maternal and/or paternal cigarette smoking in a nicotine dose-dependent manner [103–105], and our smokers produced 43% male births, down from the worldwide average of 51.4% [106]. There is emerging evidence that changes to DNA methylation as a result of maternal smoking are greater in male offspring than female offspring [107]. However, while smoking would be expected to be associated with a decrease in birthweight, particularly in male offspring [102], we found male neonates from smokers were 500 g heavier than those from the no-tobacco group while females were on average 280 g lighter. The tobacco chewer group, despite exhibiting higher mean NM levels in their blood, had 60% male births and less impact on male birthweight.

Maternal smoking and SLT use increases the risk of a small for gestation age (SGA) neonate [108, 109]. Likewise, elevated maternal glucose increases the likelihood of an earlier (spontaneous or induced) birth, and increases the likelihood of an SGA or a large for gestation age (LGA) neonate dependent upon neonatal genome [110, 111]. In Australian Aboriginal pregnancies, the immediate foetal impact of exposure to pre-gestational and gestational diabetes is different to that evidenced in Australian non-Aboriginal pregnancies. In the presence of pre-gestational diabetes, there is a slightly higher incidence of an LGA birth in Aboriginal pregnancies compared with non-Aboriginal pregnancies (32.9% versus 32.7%) and an increase in SGA births (8.2% versus 4.6%). In the presence of gestational diabetes there is an increased incidence of an LGA neonate in Aboriginal pregnancies compared with non-Aboriginal pregnancies (21.1% versus 13.3%) and the reverse for the incidence of an SGA birth in Aboriginal pregnancies compared with non-Aboriginal pregnancies (7.1% versus 8.3%) [110, 111].

In this research, the medical record of participants often recorded both pre-gestational and gestational diabetes, and accordingly, this variable was dealt with as one variable. The research findings show that whilst the mean birthweight for each group across the cohort was similar, lower birthweights were seen in the presence of tobacco exposure when there was an absence of maternal elevated glucose. Tobacco-exposed women with elevated blood glucose had higher maternal blood NM concentrations than their group counterparts without elevated glucose, and had analogous higher birthweight neonates. In the chewers, neonates exposed to elevated glucose and higher maternal NM weighed 1014 g more than the neonates of chewers not exposed to elevated glucose and lower maternal NM. This same trend existed for smokers only if a very small (900 g) pre-term 27-week gestation neonate was excluded from the elevated glucose group for analysis, in which case neonates from smokers exposed to elevated glucose weighed 472 g more than those not exposed.

Limitations

We grouped participants by their response to the interview question “have you smoked cigarettes or chewed tobacco in this pregnancy?” Surprisingly, participants with visible oral pituri quids answered “no” to this question. It became apparent that chewers did not consider pituri as tobacco. This finding was later confirmed in ethnobotanical interviews with senior Aboriginal women who rejected the notion that pituri was a tobacco plant [9]. The interview question was subsequently changed to “have you chewed pituri or mingkulpa or tobacco in this pregnancy?” Nevertheless, early participant enrolments may have been incorrectly categorised, and this may explain some high NM readings in the no-tobacco use group.

Biological samples were taken at a single time point, so the NM values do not accurately reflect the totality of tobacco and nicotine exposure during the pregnancy, and instead indicate the extent of recent exposure. This is particularly relevant when comparing smokers and chewers, where the continued use of pituri is possible within a hospital, as opposed to the need for a smoker to leave the hospital grounds for a cigarette.

The research conveniently enrolled participants who were considered to be over 28 weeks gestation based on the expected due date. Mothers who experienced early- and mid-pregnancy adverse outcomes or birth or who were transferred to a tertiary health service prior to that time were therefore not invited to participate and this may underestimate the impact of nicotine exposure on pregnancy outcomes.

Finally, the small numbers for each biological sample limits the ability to perform statistical comparisons or draw generalised conclusions. Furthermore, there are a variety of Australian Nicotiana spp. plants which grow across the expanse of Australia with the nicotine content of the individual plants impacted by their location and environmental factors such as soil, rain and temperature and their preparation for use as SLT [6, 9]. Therefore, extrapolation of the findings from this research with other Australian Aboriginal and Torres Strait Islander populations, and other Indigenous worldwide groups and non-Indigenous groups, may not be appropriate.

The most significant, individually modifable factor associated with improved maternal and neonatal outcomes is the absence of maternal cigarette smoking. For central Australian Aboriginal populations exposure to nicotine and its metabolites includes the chewing of wild tobacco plants. Pituri chewing is embedded in central Australian communities, existing as an early life ‘rite of passage’ from parent to child [9]. The pituri chewer participants may have been exposed to nicotine from the time of their own conception via their own mother’s chewing, with continued exposure through breast feeding, followed by their own uptake of pituri use in very early life. This research indicates that there is a relationship between the nicotine exposure from chewing these plants during pregnancy and adverse maternal and neonatal outcomes and that these outcomes are similar to the use of smoked tobacco, albeit, with more frequency.

Importantly, this research demonstrated that cohort mean birthweight (as a sentinel neonatal outcome variable) can be a misleading measure if not considered alongside the presence of elevated maternal glucose and tobacco use. Consideration of the role that nicotine exposure has in the development of elevated maternal glucose in pregnancy is important in mitigating the development of chronic health illness in later life. The long-term effects of the dual exposure to nicotine and elevated glucose on the developing foetus are important to public health knowledge and public health education. Future research that explores the pharmacodynamics and pharmacokinetics of nicotine metabolism in this population will provide important understandings related to these outcomes but is reliant on the collection of accurate tobacco and nicotine exposure data. Modifying the pregnancy health assessment and data collection tools to record the broader range and use of nicotine containing products will enable a more inclusive and discriminative assessment of their effects on contemporary Australian pregnancies and outcomes.

AC artery cord blood

AF Amniotic fluid

AHW: Aboriginal Health Worker

ALO: Aboriginal Liaison Officer

BM: Breast milk

CI: Confidence interval

CS: Cesarean section

g: gram

LGA: Large for gestational age

LBW: Low birthweight

HBW: High birthweight

IUGR: Intrauterine growth retardation

MB Maternal venous blood

mL: millilitres

MU Maternal urine

nAChRs: nicotinic acetylcholine receptors

NT: Northern Territory

NU1 Neonatal urine Day 1

NU3 Neonatal urine Day 3

OR: Odds ratio

SCN: Special Care Nursery

SD: Standard deviation

SGA: Small for gestational age

SIDS: Sudden infant death syndrome

SUDI: Sudden unexpected death in infancy

SLT: Smokeless tobacco

NM: Nicotine and metabolites

VC Vein cord blood

WHO: World Health Organization

Ethics approval and consent to participate.

Ethical approval was obtained from the Central Australian (#2010.06.04) and The University of Queensland Human Research Ethics Committees (#2010000548 and # 2015001429). All participants provided written informed consent prior to enrolling in the research.

Consent for publication.

Written, informed consent contained permission to publish.

Availability of data and materials.

The data generated or analysed during this aspect of the study is included in this published article.

Competing interests.

All authors report no competing interests.

Funding.

AR was supported under a Queensland Health, Health and Medical Research Fellowship, the University of Queensland School of Nursing and Midwifery, Elizabeth A. Davies Scholarship, the Queensland Centaur Memorial Fund for Nurses Scholarship, and the Australian College of Nursing PhD Scholarship.

Authors’ contributions.

AR conceived the project and designed and implemented the data collection process and analysis plan and conducted the analysis with input from EAB, FB, KS and BR. BR conducted the biochemical analysis of all biological samples. AR prepared the manuscript, and all authors reviewed and provided feedback on the final version. The authors read and approved the final manuscript.

Acknowledgements.

We acknowledge the Aboriginal Traditional Owners of the land where this research was conducted, and the Traditional Owners of the lands from which the participants came. We acknowledge and respect the role of the Ngaanyatjarra Pitjantjatjara Yankunytjatjara Central Australian Aboriginal Women’s Council and its Directors in supporting and advising the research design, and we are indebted to the participants for their involvement in this research. We thank the staff of the Alice Springs Hospital for their assistance in the data collection.

World Health Organisation: Global report on trends in prevalence of tobacco use 2000–2025, 3 edn. Geneva: WHO; 2019.
National Cancer Institute and Centres for Disease Control and Prevention: Smokeless tobacco and public health: A global perspective. Bethesda, MD: U.S. Department of Health and Human Services; 2014.
Benowitz NL, Hukkanen J, Jacob P, III: Nicotine chemistry, metabolism, kinetics and biomarkers. In: Nicotine psychopharmacology. Volume 192, edn. Edited by Henningfield JE, London ED, Pogun S: Springer Berlin Heidelberg; 2009: 29–60.
Ratsch A, Steadman KJ, Bogossian F: The pituri story: A review of the historical literature surrounding traditional Australian Aboriginal use of nicotine in central Australia. J Ethnobiol Ethnomed. 2010;6:26. doi:10.1186/1746-4269-6-26
Moghbel N, Ryu B, Cabot PJ, Ratsch A, Steadman KJ: In vitro cytotoxicity of Nicotiana gossei leaves, used in the Australian Aboriginal smokeless tobacco known as pituri or mingkulpa. Toxicol Lett. 2016;254:45–51. doi:10.1016/j.toxlet.2016.05.011
Moghbel N, Ryu B, Ratsch A, Steadman KJ: Nicotine alkaloid levels, and nicotine to nornicotine conversion, in Australian Nicotiana species used as chewing tobacco. Heliyon. 2017;3(11):e00469-e00469. doi:10.1016/j.heliyon.2017.e00469
Wilhelm J, Mishina E, Viray L, Paredes A, Pickworth WB: The pH of smokeless tobacco determines nicotine buccal absorption: Results of a randomized crossover trial. Clin Pharmacol Ther. 2021. doi:10.1002/cpt.2493
Gupta SK, Benowitz NL, Jacob P, 3rd, Rolf CN, Gorsline J: Bioavailability and absorption kinetics of nicotine following application of a transdermal system. Br J Clin Pharmacol. 1993;36(3):221–227. doi:10.1111/j.1365-2125.1993.tb04221.x
Ratsch A, Mason A, Rive L, Bogossian F, Steadman K: The pituri learning story: Central Australian Aboriginal women’s knowledge and practices around the use of Nicotiana spp. As a chewing tobacco. In: Rural Remote Health. vol. July-Sep; 2017: 4044.
Luck W, Nau H: Nicotine and cotinine concentrations in serum and urine of infants exposed via passive smoking or milk from smoking mothers. The Journal of Pediatrics. 1985;107(5):816–820. doi:10.1016/s0022-3476(85)80427-3
Lambers DS, Clark KE: The maternal and fetal physiologic effects of nicotine. Semin Perinatol. 1996;20(2):115–126. doi:10.1016/s0146-0005(96)80079-6
Benowitz NL: Clinical pharmacology of nicotine. Annu Rev Med. 1986;37:21–32. doi:10.1146/annurev.me.37.020186.000321
Grenhoff J, Svensson TH: Pharmacology of nicotine. Br J Addict. 1989;84(5):477–492. doi:10.1111/j.1360-0443.1989.tb00604.x
Benowitz NL, Kuyt F, Jacob P, 3rd, Jones RT, Osman AL: Cotinine disposition and effects. Clin Pharmacol Ther. 1983;34(5):604–611. doi:10.1038/clpt.1983.222
Hukkanen J, Jacob P, 3rd, Benowitz NL: Metabolism and disposition kinetics of nicotine. Pharmacol Rev. 2005;57(1):79–115. doi:10.1124/pr.57.1.3
Dempsey D, Jacob P, 3rd, Benowitz NL: Accelerated metabolism of nicotine and cotinine in pregnant smokers. J Pharmacol Exp Ther. 2002;301(2):594–598. doi:10.1124/jpet.301.2.594
Arger CA, Taghavi T, Heil SH, Skelly J, Tyndale RF, Higgins ST: Pregnancy-induced increases in the nicotine metabolite ratio: Examining changes during antepartum and postpartum. Nicotine Tob Res. 2019;21(12):1706–1710. doi:10.1093/ntr/nty172
Dempsey D, Jacob P, 3rd, Benowitz NL: Nicotine metabolism and elimination kinetics in newborns. Clin Pharmacol Ther. 2000;67(5):458–465. doi:10.1067/mcp.2000.106129
Ratsch A, Bogossian F: Smokeless tobacco use in pregnancy: An integrative review of the literature. Int J Public Health. 2014;59(4):599–608. doi:10.1007/s00038-014-0558-6
England LJ, Kim SY, Shapiro-Mendoza CK, Wilson HG, Kendrick JS, Satten GA, Lewis CA, Tucker MJ, Callaghan WM: Effects of maternal smokeless tobacco use on selected pregnancy outcomes in Alaska Native women: A case-control study. Acta Obstet Gynecol Scand. 2013;92(6):648–655. doi:10.1111/aogs.12124
Hossain MS, Kypri K, Rahman B, Milton AH: Smokeless tobacco consumption and stillbirth: Population-based case-control study in rural Bangladesh. Drug Alcohol Rev. 2018;37(3):414–420. doi:10.1111/dar.12566
Ganganahalli P, Pratinidhi A, Patil JA, Kakade SV: Smokeless tobacco use & anaemia among pregnant women in Karad Taluk Western Maharashtra: A cross sectional study. Ntl J of Community Med. 2015;6(4):622–625. http://www.njcmindia.org/home/abstrct/758/Oct-Dec_2015
Inamdar AS, Croucher RE, Chokhandre MK, Mashyakhy MH, Marinho VC: Maternal smokeless tobacco use in pregnancy and adverse health outcomes in newborns: A systematic review. Nicotine Tob Res. 2015;17(9):1058–1066. doi:10.1093/ntr/ntu255
Pineles BL, Hsu S, Park E, Samet JM: Systematic review and meta-analyses of perinatal death and maternal exposure to tobacco smoke during pregnancy. Am J Epidemiol. 2016;184(2):87–97. doi:10.1093/aje/kwv301
Pineles BL, Park E, Samet JM: Systematic review and meta-analysis of miscarriage and maternal exposure to tobacco smoke during pregnancy. Am J Epidemiol. 2014;179(7):807–823. doi:10.1093/aje/kwt334
Solomon CG, Willett WC, Carey VJ, Rich-Edwards J, Hunter DJ, Colditz GA, Stampfer MJ, Speizer FE, Spiegelman D, Manson JE: A prospective study of pregravid determinants of gestational diabetes mellitus. JAMA. 1997;278(13):1078–1083. doi:10.1001/jama.1997.03550130052036
England LJ, Levine RJ, Qian C, Soule LM, Schisterman EF, Yu KF, Catalano PM: Glucose tolerance and risk of gestational diabetes mellitus in nulliparous women who smoke during pregnancy. Am J Epidemiol. 2004;160(12):1205–1213. doi:10.1093/aje/kwh340
Kim MK, Han K, You SY, Kwon HS, Yoon KH, Lee SH: Prepregnancy smoking and the risk of gestational diabetes requiring insulin therapy. Sci Rep. 2020;10(1):13901. doi:10.1038/s41598-020-70873-7
Rogers JM: Tobacco and pregnancy. Reprod Toxicol. 2009;28(2):152–160. doi:10.1016/j.reprotox.2009.03.012
Gonzalez-Quintero VH, Istwan NB, Rhea DJ, Rodriguez LI, Cotter A, Carter J, Mueller A, Stanziano GJ: The impact of glycemic control on neonatal outcome in singleton pregnancies complicated by gestational diabetes. Diabetes Care. 2007;30(3):467–470. doi:10.2337/dc06-1875
Jones CW: Gestational diabetes and its impact on the neonate. Neonatal Netw. 2001;20(6):17–23. doi:10.1891/0730-0832.20.6.17
Pintaudi B, Fresa R, Dalfra M, Dodesini AR, Vitacolonna E, Tumminia A, Sciacca L, Lencioni C, Marcone T, Lucisano G et al: The risk stratification of adverse neonatal outcomes in women with gestational diabetes (strong) study. Acta Diabetol. 2018;55(12):1261–1273. doi:10.1007/s00592-018-1208-x
Makgoba M, Savvidou MD, Steer PJ: The effect of maternal characteristics and gestational diabetes on birthweight. BJOG. 2012;119(9):1091–1097. doi:10.1111/j.1471-0528.2012.03388.x
Tracy SK, Tracy MB, Sullivan E: Admission of term infants to neonatal intensive care: A population-based study. Birth. 2007;34(4):301–307. doi:10.1111/j.1523-536X.2007.00188.x
Slotkin T: Expert opinions: Nicotine: Interview with Professor Theodore Slotkin. In: ABC Online - Quantum. Australia: Australia Broadcasting Corporation; 1997.
England LJ, Aagaard K, Bloch M, Conway K, Cosgrove K, Grana R, Gould TJ, Hatsukami D, Jensen F, Kandel D et al: Developmental toxicity of nicotine: A transdisciplinary synthesis and implications for emerging tobacco products. Neurosci Biobehav Rev. 2017;72:176–189. doi:10.1016/j.neubiorev.2016.11.013
Slotkin TA, Lappi SE, McCook EC, Lorber BA, Seidler FJ: Loss of neonatal hypoxia tolerance after prenatal nicotine exposure: Implications for sudden infant death syndrome. Brain Res Bull. 1995;38(1):69–75. doi:10.1016/0361-9230(95)00073-n
Shapiro-Mendoza CK, Parks S, Lambert AE, Camperlengo L, Cottengim C, Olson C: The epidemiology of sudden infant death syndrome and sudden unexpected infant deaths: Diagnostic shift and other temporal changes: University of Adelaide Press, Adelaide (AU); 2018.
eTG. Therapeutic guidelines 2015 [cited June 102015].[Available from: https://www.tg.org.au/etg_demo/desktop/tgc/plg/breastfeeding_n.htm]
U.S. Food & Drug Administration. Tobacco products 2021 [cited 21 September2021].[Available from: https://www.fda.gov/tobacco-products]
Therapeutic Goods Administration. Category D drugs 2015 [cited May 102016].[Available from: http://www.tga.gov.au/prescribing-medicines-pregnancy-database]
Cornelius MD, Goldschmidt L, Day NL: Prenatal cigarette smoking: Long-term effects on young adult behavior problems and smoking behavior. Neurotoxicol Teratol. 2012;34(6):554–559. doi:10.1016/j.ntt.2012.09.003
Berlin I, Oncken C: Maternal smoking during pregnancy and negative health outcomes in the offspring. Nicotine Tob Res. 2018;20(6):663–664. doi:10.1093/ntr/nty035
Kataria Y, Gaewsky L, Ellervik C: Prenatal smoking exposure and cardio-metabolic risk factors in adulthood: A general population study and a meta-analysis. Int J Obes (Lond). 2019;43(4):763–773. doi:10.1038/s41366-018-0206-y
Lawder R, Whyte B, Wood R, Fischbacher C, Tappin DM: Impact of maternal smoking on early childhood health: A retrospective cohort linked dataset analysis of 697 003 children born in Scotland 1997–2009. BMJ Open. 2019;9(3):e023213. doi:10.1136/bmjopen-2018-023213
Mittal S: Smoking and tobacco use: Ill effects on reproductive, maternal, newborn, child health, and adolescent (rmncha) program—a review. Ann Natl Acad Med Sci. 2019;55(02):065–073. doi:10.1055/s-0039-1694071
Australian Institute of Health and Welfare: National perinatal data collection (NPDC), vol. 2020. Canberra: Australian Government; 2020.
Australian Institute of Health and Welfare. Australia's mothers and babies 2021 [cited 8 July2021].[Available from: https://www.aihw.gov.au/reports/mothers-babies/australias-mothers-babies-data-visualisations/contents/antenatal-period/smoking]
Zhang X, Johnstone K: Northern Territory midwives’ collection. Mothers and babies 2005. Darwin: Department of Health and Families; 2009.
Li L, O’Neil L: Mothers and babies 2016: Northern Territory midwives’ collection. Darwin: Department of Health; 2019.
Australian Institute of Health and Welfare: Australia's mothers and babies 2013 in brief. Canberra: AIHW; 2015.
Hall J, Case A, O'Neil L: Northern Territory midwives’ collection. Mothers and babies 2013. Darwin: Health Gains Planning Branch; 2015.
Australian Institute of Health and Welfare. National Indigenous Australian Agency. Aboriginal and Torres Strait Islander health performance framework 2021 [cited 20 October2021].[Available from: https://www.indigenoushpf.gov.au/measures/1-01-low-birthweight]
Ratsch A, Bogossian F, Steadman K: Central Australian Aboriginal women's pregnancy, labour and birth outcomes following maternal smokeless tobacco (pituri) use, cigarette use or no-tobacco use: A prospective cohort study. BMC Public Health. 2021;21(1):814. doi:10.1186/s12889-021-10872-z
Ratsch A, Bogossian F, Burmeister EA, Steadman K: Central Australian Aboriginal women's placental and neonatal outcomes following maternal smokeless tobacco, cigarette or no tobacco use. Aust N Z J Public Health. 2021;. doi:10.1111/1753-6405.13186
Ratsch A, Steadman K, Ryu B, Bogossian F: Tobacco and pituri use in pregnancy: A protocol for measuring maternal and perinatal exposure and outcomes in central Australian Aboriginal women. Methods Protoc. 2019;2(2):47. doi:10.3390/mps2020047
Hurt RD, Renner CC, Patten CA, Ebbert JO, Offord KP, Schroeder DR, Enoch CC, Gill L, Angstman SE, Moyer TP: Iqmik–a form of smokeless tobacco used by pregnant alaska natives: Nicotine exposure in their neonates. J Matern Fetal Neonatal Med. 2005;17(4):281–289. doi:10.1080/14767050500123731
Li Z, Zeki R, Hilder L, Sullivan E: Australia's mothers and babies 2011. Canberra: Australian Institute of Health and Welfare; 2013.
Thompson F: Northern Territory midwives’ collection. Mothers and babies 2011. Darwin: Department of Health; 2014.
Health Gains Planning Unit: Central Australian Regional Plan (2010–2012) 2012.
Benowitz N, Porchet H, Sheiner L, Jacob P: Nicotine absorption and cardiovascular effects with smokeless tobacco use: Comparison with cigarettes and nicotine gum. Clinical Pharmacology Therapy. 1988;44(1):23–28.
George L, Granath F, Johansson AL, Cnattingius S: Self-reported nicotine exposure and plasma levels of cotinine in early and late pregnancy. Acta Obstet Gynecol Scand. 2006;85(11):1331–1337. doi:10.1080/00016340600935433
World Health Organization: Smokeless tobacco and some tobacco-specific n-nitrosamines, vol. 89. Lyon, France: WHO; 2007.
Luck W, Nau H, Hansen R, Steldinger R: Extent of nicotine and cotinine transfer to the human fetus, placenta and amniotic fluid of smoking mothers. Dev Pharmacol Ther. 1985;8(6):384–395. doi:10.1159/000457063
Habek D, Habek JC, Ivanisevic M, Djelmis J: Fetal tobacco syndrome and perinatal outcome. Fetal Diagn Ther. 2002;17(6):367–371. doi:10.1159/000065387
Dahlstrom A, Ebersjo C, Lundell B: Nicotine exposure in breastfed infants. Acta Paediatr. 2004;93(6):810–816. doi:10.1111/j.1651-2227.2004.tb03023.x
Steldinger R, Luck W, Nau H: Half lives of nicotine in milk of smoking mothers: Implications for nursing. J Perinat Med. 1988;16(3):261–262. https://www.ncbi.nlm.nih.gov/pubmed/3210114
Benowitz NL, Dains KM, Dempsey D, Yu L, Jacob P, 3rd: Estimation of nicotine dose after low-level exposure using plasma and urine nicotine metabolites. Cancer Epidemiol Biomarkers Prev. 2010;19(5):1160–1166. doi:10.1158/1055-9965.EPI-09-1303
The National Health and Medical Research Council, the Australian Research Council, and Universities Australia: National statement on ethical conduct in human research 2007 (updated 2018). Canberra: Commonwealth of Australia; 2018.
Gilligan C, Sanson-Fisher R, Eades S, Wenitong M, Panaretto K, D'Este C: Assessing the accuracy of self-reported smoking status and impact of passive smoke exposure among pregnant Aboriginal and Torres Strait Islander women using cotinine biochemical validation. Drug Alcohol Rev. 2010;29(1):35–40. doi:10.1111/j.1465-3362.2009.00078.x
Aurrekoetxea JJ, Murcia M, Rebagliato M, Lopez MJ, Castilla AM, Santa-Marina L, Guxens M, Fernandez-Somoano A, Espada M, Lertxundi A et al: Determinants of self-reported smoking and misclassification during pregnancy, and analysis of optimal cut-off points for urinary cotinine: A cross-sectional study. BMJ Open. 2013;3(1):e002034. doi:10.1136/bmjopen-2012-002034
Stragierowicz J, Mikolajewska K, Zawadzka-Stolarz M, Polanska K, Ligocka D: Estimation of cutoff values of cotinine in urine and saliva for pregnant women in Poland. Biomed Res Int. 2013;2013:386784. doi:10.1155/2013/386784
Perez-Stable EJ, Herrera B, Jacob P, 3rd, Benowitz NL: Nicotine metabolism and intake in black and white smokers. JAMA. 1998;280(2):152–156. doi:10.1001/jama.280.2.152
Caraballo RS, Giovino GA, Pechacek TF, Mowery PD, Richter PA, Strauss WJ, Sharp DJ, Eriksen MP, Pirkle JL, Maurer KR: Racial and ethnic differences in serum cotinine levels of cigarette smokers: Third national health and nutrition examination survey, 1988–1991. JAMA. 1998;280(2):135–139. doi:10.1001/jama.280.2.135
Wang H, Park SL, Stram DO, Haiman CA, Wilkens LR, Hecht SS, Kolonel LN, Murphy SE, Le Marchand L: Associations between genetic ancestries and nicotine metabolism biomarkers in the multiethnic cohort study. Am J Epidemiol. 2015;182(11):945–951. doi:10.1093/aje/kwv138
Maddatu J, Anderson-Baucum E, Evans-Molina C: Smoking and the risk of type 2 diabetes. Transl Res. 2017;184:101–107. doi:10.1016/j.trsl.2017.02.004
Willi C, Bodenmann P, Ghali WA, Faris PD, Cornuz J: Active smoking and the risk of type 2 diabetes: A systematic review and meta-analysis. JAMA. 2007;298(22):2654–2664. doi:10.1001/jama.298.22.2654
Barbour LA, McCurdy CE, Hernandez TL, Kirwan JP, Catalano PM, Friedman JE: Cellular mechanisms for insulin resistance in normal pregnancy and gestational diabetes. Diabetes Care. 2007;30 Suppl 2(Supplement 2):S112-119. doi:10.2337/dc07-s202
Voaklander B, Rowe S, Sanni O, Campbell S, Eurich D, Ospina MB: Prevalence of diabetes in pregnancy among Indigenous women in Australia, Canada, New Zealand, and the USA: A systematic review and meta-analysis. The Lancet Global Health. 2020;8(5):e681-e698. doi:10.1016/s2214-109x(20)30046-2
Australian Institute of Health and Welfare: Australia's mothers and babies data visualisations. Cat. No. Per 101. Canberra: AIHW; 2020.
Damm P, Houshmand-Oeregaard A, Kelstrup L, Lauenborg J, Mathiesen ER, Clausen TD: Gestational diabetes mellitus and long-term consequences for mother and offspring: A view from Denmark. Diabetologia. 2016;59(7):1396–1399. doi:10.1007/s00125-016-3985-5
Conde-Agudelo A, Althabe F, Belizan JM, Kafury-Goeta AC: Cigarette smoking during pregnancy and risk of preeclampsia: A systematic review. Am J Obstet Gynecol. 1999;181(4):1026–1035. doi:10.1016/s0002-9378(99)70341-8
Karumanchi SA, Levine RJ: How does smoking reduce the risk of preeclampsia? Hypertension. 2010;55(5):1100–1101. doi:10.1161/HYPERTENSIONAHA.109.148973
England L, Zhang J: Smoking and risk of preeclampsia: A systematic review. Front Biosci. 2007;12:2471–2483. doi:10.2741/2248
Subramoney S, Gupta PC: Anemia in pregnant women who use smokeless tobacco. Nicotine Tob Res. 2008;10(5):917–920. doi:10.1080/14622200802027206
Pratinidhi A, Gandham S, Shrotri A, Patil A, Pardeshi S: Use of 'mishri' a smokeless form of tobacco during pregnancy and its perinatal outcome. Indian J Community Med. 2010;35(1):14–18. doi:10.4103/0970-0218.62547
Capra L, Tezza G, Mazzei F, Boner AL: The origins of health and disease: The influence of maternal diseases and lifestyle during gestation. Ital J Pediatr. 2013;39(1):7. doi:10.1186/1824-7288-39-7
Willcocks B, McAuliffe GN, Baird RW: Dwarf tapeworm (Hymenolepis nana): Characteristics in the Northern Territory 2002–2013. J Paediatr Child Health. 2015;51(10):982–987. doi:10.1111/jpc.12885
Roulette CJ, Mann H, Kemp BM, Remiker M, Roulette JW, Hewlett BS, Kazanji M, Breurec S, Monchy D, Sullivan RJ et al: Tobacco use vs. Helminths in Congo basin hunter-gatherers: Self-medication in humans? Evol Hum Behav. 2014;35(5):397–407. doi:10.1016/j.evolhumbehav.2014.05.005
Stewart GG: A history of the medicinal use of tobacco 1492–1860. Med Hist. 1967;11(3):228–268. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1033728/
Berlowitz I, Torres EG, Walt H, Wolf U, Maake C, Martin-Soelch C: "Tobacco is the chief medicinal plant in my work": Therapeutic uses of tobacco in Peruvian Amazonian medicine exemplified by the work of a Maestro Tabaquero. Front Pharmacol. 2020;11(1600):594591. doi:10.3389/fphar.2020.594591
Sastry BV, Chance MB, Hemontolor ME, Goddijn-Wessel TA: Formation and retention of cotinine during placental transfer of nicotine in human placental cotyledon. Pharmacology. 1998;57(2):104–116. doi:10.1159/000028231
Bruin JE, Kellenberger LD, Gerstein HC, Morrison KM, Holloway AC: Fetal and neonatal nicotine exposure and postnatal glucose homeostasis: Identifying critical windows of exposure. J Endocrinol. 2007;194(1):171–178. doi:10.1677/JOE-07-0050
Holloway AC, Lim GE, Petrik JJ, Foster WG, Morrison KM, Gerstein HC: Fetal and neonatal exposure to nicotine in wistar rats results in increased beta cell apoptosis at birth and postnatal endocrine and metabolic changes associated with type 2 diabetes. Diabetologia. 2005;48(12):2661–2666. doi:10.1007/s00125-005-0022-5
von Kries R, Toschke AM, Koletzko B, Slikker W, Jr.: Maternal smoking during pregnancy and childhood obesity. Am J Epidemiol. 2002;156(10):954–961. doi:10.1093/aje/kwf128
Kamiya M, Suzuki K, Yamagata Z: Effect of maternal active smoking during pregnancy on the trajectory of childhood body mass index: A multilevel analysis using quartiles of birthweight. Tob Induc Dis. 2020;18:34. doi:10.18332/tid/119117
Nordenstam F, Lundell B, Edstedt Bonamy AK, Raaschou P, Wickstrom R: Snus users had high levels of nicotine, cotinine and 3-hydroxycotinine in their breastmilk, and the clearance was slower than in smoking mothers. Acta Paediatr. 2019;108(7):1250–1255. doi:10.1111/apa.14602
Gao YJ, Holloway AC, Su LY, Takemori K, Lu C, Lee RM: Effects of fetal and neonatal exposure to nicotine on blood pressure and perivascular adipose tissue function in adult life. Eur J Pharmacol. 2008;590(1–3):264–268. doi:10.1016/j.ejphar.2008.05.044
Borowitz JL, Isom GE: Nicotine and type 2 diabetes. Toxicol Sci. 2008;103(2):225–227. doi:10.1093/toxsci/kfn050
Kohler E, Bretschneider D, Rabsilber A, Weise W, Jorch G: Assessment of prenatal smoke exposure by determining nicotine and its metabolites in maternal and neonatal urine. Hum Exp Toxicol. 2001;20(1):1–7. doi:10.1191/096032701669841404
Luck W, Nau H: Nicotine and cotinine concentrations in serum and milk of nursing smokers. Br J Clin Pharmacol. 1984;18(1):9–15. doi:10.1111/j.1365-2125.1984.tb05014.x
Tayie FA, Powell C: Sex differences in the association between prenatal smoking and decreased birthweight, and intensive health care of the neonate. Behav Med. 2012;38(4):138–142. doi:10.1080/08964289.2012.703977
Fukuda M, Fukuda K, Shimizu T, Andersen CY, Byskov AG: Parental periconceptional smoking and male: Female ratio of newborn infants. Lancet. 2002;359(9315):1407–1408. doi:10.1016/S0140-6736(02)08362-9
Koshy G, Delpisheh A, Brabin BJ: Parental smoking and increased likelihood of female birth. Arch Dis Child. 2008;93(Suppl 2):ps531-ps531.
Khan UA, Adil MM: Effect of number of cigarettes daily consumed on offspring sex ratio. In: Medical management of chemical and biological casualties. edn. Edited by Tonev S, Kanev K, Dishovsky C. Sofia: Military Medical Academy; 2009: 189–196.
World Bank Group. Sex ratio at birth (male births per female births) 2018 [cited [Available from: https://data.worldbank.org/indicator/SP.POP.BRTH.MF]
Nakamura A, Francois O, Lepeule J: Epigenetic alterations of maternal tobacco smoking during pregnancy: A narrative review. Int J Environ Res Public Health. 2021;18(10):5083. doi:10.3390/ijerph18105083
Cnattingius S: The epidemiology of smoking during pregnancy: Smoking prevalence, maternal characteristics, and pregnancy outcomes. Nicotine Tob Res. 2004;6 Suppl 2(Suppl 2):S125-140. doi:10.1080/14622200410001669187
Baba S, Wikstrom AK, Stephansson O, Cnattingius S: Changes in snuff and smoking habits in Swedish pregnant women and risk for small for gestational age births. BJOG. 2013;120(4):456–462. doi:10.1111/1471-0528.12067
Porter C, Skinner T, Ellis I: What is the impact of diabetes for Australian Aboriginal women when pregnant? Diabetes Res Clin Pract. 2011;93(1):e29-32. doi:10.1016/j.diabres.2011.03.013
Ahmed MA, Bailey HD, Pereira G, White SW, Wong K, Shepherd CCJ: Trends and burden of diabetes in pregnancy among Aboriginal and non-Aboriginal mothers in western Australia, 1998–2015. BMC Public Health. 2022;22(1):263. doi:10.1186/s12889-022-12663-6

No competing interests reported.

Additionalfile1BiochemicalSampleAnalysisMethods.docx

Download PDF

Editorial decision: Major revision
24 Jun, 2022
Reviewers agreed at journal
13 Jun, 2022
Reviews received at journal
11 Jun, 2022
Reviewers agreed at journal
01 Jun, 2022
Reviewers invited by journal
21 Apr, 2022
Editor assigned by journal
30 Mar, 2022
Editor invited by journal
22 Mar, 2022
Submission checks completed at journal
22 Mar, 2022
First submitted to journal
13 Mar, 2022

You are reading this latest preprint version

Higher blood nicotine concentrations following smokeless tobacco (pituri) and cigarette use linked to adverse pregnancy outcomes for central Australian Aboriginal pregnancies

Status:

Version 1

Abstract

Figures

Background

Methods

Biological data collection, storage and analysis

Data analysis

Ethical considerations

Results

Nicotine and metabolite concentrations

Relationship of nicotine concentrations with maternal outcomes

Relationship between maternal NM levels with neonatal and placental outcomes

Discussion

Maternal nicotine exposure and outcomes

Neonatal nicotine exposure and outcomes

Limitations

Conclusion

Abbreviations

Declarations

References

Additional Declarations

Supplementary Files

Status:

Version 1