Adverse pregnancy outcomes can be influenced by various factors that are present prior to or emerged during pregnancy. The present study was a survey carried out for measuring the prevalence of pregnancy outcomes and its association with potential risk factors.
The socio-demographic profile of women is certainly different for women residing in the tribal and nontribal area. This is important to note because the outcomes are also influenced by these factors. Although rarely practised in western countries, consanguineous marriages are seen throughout India. As shown by the India Human Development Survey (IHDS, 2004-2005) data, they were predominant in the Southern States ranging from 28% to 38% [15]. Prevalence in Maharashtra was also high (28%). In the present study, the prevalence of consanguineous marriage was 17.6% which is lower than the reported studies from rural South India, ranging from 20.3 to 36% [16,17,18]. This lower prevalence in the present study may be due to a declining trend consequent to education and modernisation.
In the present study, only 5.6% of women reported tobacco consumption during pregnancy which is less than other studies [19,20,21]. Amongst all forms of tobacco, women from India indulge more in applying Mishri (roasted tobacco) on gums and teeth, which was also observed in this study. Alcohol consumption in Indian women is less compared to women from western countries, which decreases further in pregnancy [22,23]. Alcohol consumption was very less in the study, which was lower than the consumption reported by Bellad MB et al. from India [16].
Farming is a major occupation in rural and tribal parts of India, and various pesticides are commonly used to protect the crops. Pesticide spraying on grapes is a highly prevalent seasonal work in the area. Exposure to various pesticides during pregnancy has been identified as a risk factor for adverse pregnancy outcomes; however, results are not consistent [24,25,26,27]. Association was dependent on various factors like the type of pesticide, the period of gestation, duration and amount of exposure. In this study, only 2.3% of women reported direct exposure to pesticides during pregnancy. The reason may be the non-involvement of women in the actual spraying of pesticides. This exposure to pesticides was not found associated with any of the adverse pregnancy outcomes.
Domestic violence during pregnancy was reported by only 0.8% of women, which was lower than previous reports from different states of India that ranged from 7.1% - 18% [28,29,30,31]. Considering Indian culture, women do not divulge such information, so that these figures may be just the tip of the iceberg. The pre-existing illness like endocrine abnormalities, heart disease, liver disease, etc., in the pregnant woman, can have adverse pregnancy outcomes over and above risk to maternal health [32,33,34]. In the present study, 2.2% of women had reported pre-existing illness; however, there is a dearth of information about the prevalence of pre-existing illness in pregnant women in the community.
When the distribution of these potential risk factors was compared in tribal versus nontribal area, consanguineous marriage, heavy work in the last six months of pregnancy, tobacco and alcohol consumption, exposure to pesticides, and domestic violence were significantly more in the tribal area, which maybe because of the socio-cultural differences in these areas. Some studies have compared the socio-demographic profile of women from the tribal and nontribal area; however, a comparison of the distribution of such potential risk factors in these two groups of women are extremely rare. Alcohol consumption was higher in tribal women, which is similar to the observation of Mohan D et al. [35] who categorised tribal women in the high-risk group for alcohol consumption. Only pre-existing illness at the time of conception was more in nontribal area than tribal which may be because of better availability and accessibility of health care services in nontribal area than tribal which has led to more detection of existing illnesses.
Abortion
In the present study, 4.1% of women reported abortion which is consistent with estimated 47·0/1000 women abortions in India in 2015 [36]. Performing hard manual work, including lifting heavy weights during early pregnancy, is associated with abortion which is once again confirmed in this study. In the present study, existing maternal illness had three times the risk of abortion, which was also identified as a risk factor for abortion in other studies [37,38,39]. More abortions occurred in the nontribal area compared with tribal (5.1% vs 2.3%), and the difference was statistically significant. Residence in the tribal area has a protective factor. This may be due to more availability of various means of abortion like access to abortifacient medicines, health facilities, and affordability to avail these facilities. However, this could not be confirmed, as we did not differentiate between spontaneous and induced abortion. It was not consistent with observation reported by Niswade A et al. for tribal and rural communities from Maharashtra, India [40]. Consanguineous marriage was not associated with abortion in the present study; however, few studies observed an association between consanguineous marriage and abortion [16,17]. Whereas no association was observed in one study [18]. Studies have shown an association of alcohol consumption during pregnancy, especially the first trimester, with an increased risk of abortions [41,42]. A review by Henderson et al. 2007 did not find consistent evidence for increased risk of spontaneous abortion with light to moderate prenatal alcohol exposure [43]. Association of alcohol consumption with abortion was not seen in this study.
Stillbirth
Stillbirth was reported by 1.6% of mothers, which is similar to Doke P et al., who reported stillbirth of 1.55% from rural Maharashtra, India [44]. Other studies from India have reported a stillbirth rate ranging from 10-20 per 1000 birth [45,46]. In the present study, consanguineous marriage was identified as a significant risk factor for stillbirth, consistent with Bellad MB et al. and Kulkarni ML et al.[16,47]. Tobacco consumption increased the risk of stillbirth by two times which is consistent with other studies [48,49,50]. The meta-analysis by Marufu TC et al. 2015 reported maternal smoking during pregnancy increased the risk of stillbirth by 47% and confirmed a strong dose-response effect [51]. Many studies have identified alcohol consumption during pregnancy as a risk factor for stillbirth, which was not seen in this study [52,53]. It may be because of a small number of women consuming alcohol in the present study. Existing maternal illnesses like thyroid dysfunction or diabetes mellitus are associated with stillbirth, which is similar to the present study [37,42,54]. Domestic violence was not associated with stillbirth, which is not consistent with previous studies [28,55].
Preterm
In the present study, reported preterm birth was 4.1% which was lower than the range of 9% to 18% reported by various Indian studies [55,56,57], and the global estimate of 10.6% [58]. One of the reasons may be that these studies are either past studies or not from a progressive state. The reporting of the preterm birth rate was less than expected, which may be because of the recall bias and inability of mothers in reporting the exact pregnancy duration. An overall high proportion of women (37.26%) were unable to quantify the period of gestation in weeks, and particularly among women from tribal areas, the proportion was 46.63%. Less preterm births were reported in tribal women compared to nontribal; the difference was statistically significant. Although the non-response rate was more among tribal women, the explicit reasons for the lower prevalence of preterm babies could not be elicited.
Consanguineous marriage has been found associated with preterm births in previous studies; however, it was not observed in the present study [59,60]. In the present study, heavy work during the last six months of pregnancy was identified as a risk factor for preterm birth. Knudsen IR et al. from Denmark reported an increased risk of preterm birth in mothers performing heavy work like lifting heavy loads during pregnancy but not in women performing physically strenuous work [61]. Snijder CA et al. from Netherland did not find consistent significant associations between physically demanding work and low birth weight or preterm delivery [62].
Studies have shown the association of tobacco consumption or smoking during pregnancy with preterm birth which is due to various obstetric factors [63,64]. Risk is shown to increase with the amount of smoke [65]. Quitting smoking, especially early in pregnancy, decreases the risk of preterm birth [65]. However, in the present study, tobacco consumption was not associated with preterm birth. The role of alcohol consumption in preterm birth is controversial, and no association was found in this study [43,65]. Few studies have identified exposure to pesticides as a risk factor for preterm birth; however, findings are not consistent [24,66,67]. The present study did not find any association of exposure to pesticides with preterm birth. A meta-analysis by Shah PS et al. 2010 reported a 46% risk of preterm birth in women exposed to domestic violence during pregnancy; however, it was not observed in the present study [68]. Existing maternal illnesses like diabetes mellitus or liver disorder are found to be associated with preterm birth, but no such association was found in the present study [32,39,69].
Low Birth Weight
The study reported 11.2% LBW, which was lower than the global estimate of 14.6% [70], and the range of 17% to 36.8% reported from rural or tribal settings of India [71,72,73]. Performing heavy work during the last six months of pregnancy was associated with LBW, which was similar to the observation made by Kumar M et al.[71]. Use of any form of tobacco, including smokeless tobacco, was associated with harmful effects in the form of LBW; however, this study did not find such association [63,74]. Similarly, in the present study, no association of maternal alcohol consumption during pregnancy was found with LBW. Like premature birth, exposure to various pesticides during pregnancy has been identified as a risk factor for LBW; however, results are not consistent [24,25]. This study also did not find such an association. The association between pesticides and LBW depends on various factors like the type of pesticide, the period of gestation, duration and amount of exposure.
Gebremedhin M et al., in their study, had observed five times the risk of LBW in women having chronic medical illness during pregnancy [75]. In the present study, such a risk was 1.8 times high. Domestic violence was found to be associated with LBW in some studies; however, it is not observed in this study [70,76]. Residence in the tribal area was identified as a risk factor for LBW, which was similar to the finding of Niswade A et al.[40]. This may be because of various socio-demographic and environmental factors like maternal age, education, nutrition, Ante Natal Care (ANC) visits, availability and accessibility of health care facility etc.
Congenital Physical Defect
Congenital physical defects were present in 2.6% of babies, which is slightly more than the estimated national pooled prevalence of 184.48 per 10,000 births reported by Bhide P et al. 2018 in his meta-analysis [76]. In the present study, the perception of women about congenital physical defects pertained mostly to physical defects. Actual assessment of genetic or metabolic physical defects is difficult to assess in the field. Similar to previous studies, the present study found consanguineous marriage as a risk factor for a congenital physical defect in the baby [47,77,78]. The proportion of congenital physical birth defects may be reduced by creating awareness about the effects of consanguineous marriages. This intervention is not attempted and probably may require minimal resources. Moreover, it will have collateral benefits on biochemical and functional congenital anomalies.
It was also found to be associated with heavy work during the last six months of pregnancy. Tobacco consumption was identified as a risk factor for a congenital physical defect. A meta-analysis by Little J et al. 2004 has reported an association of maternal smoking with congenital oro-facial clefts [79], whereas Hackshaw A et al., in his systematic review, has found a significant association with many other birth defects like a heart defect, musculoskeletal defect, oro-facial clefts etc.[80]. Alcohol consumption during pregnancy was identified as a risk factor for a congenital physical defect in off-springs [81,82]; however, it was not observed in this study. Existing illness in pregnant women has been identified as a risk factor for congenital physical defects in a few studies but was not seen in this study [77,83].
Early Neonatal Death
Early neonatal death was 0.59% which was lower than the estimated early neonatal death rate of 20 per 1000 live births in India for the year 2017 [84]. This may be due to lower rates of preterm deliveries and low birth weight babies and a high rate of institutional deliveries in the study area. Ahmed et al. reported a 2.3 times high risk of neonatal mortality among mothers who experienced violence during pregnancy [28]. No such association was found in the present study.
Strengths And Limitations
It was a large study involving more than nine thousand women from four blocks. It included various adverse pregnancy outcomes as well as various risk factors. It was conducted with the help of existing health care workers. However, the overall prevalence of socio-demographic characteristics and risk factors considered in the present study may not be a true reflection of the community in general because 35% of the women in the study were from tribal area. It also implies that it is pertinent for states having a high tribal population. Although the non-response rate was more among tribal women, the explicit reasons for the lower prevalence of preterm babies could not be elicited. Details regarding pre-existing illness were not studied. The details of abortion were not collected.