Evaluating the Link between Cord Gas Parameters and Apgar Scores in High-Risk Pregnancies: Insights from a One-Year Study in Qatar

doi:10.21203/rs.3.rs-3307739/v1

This prospective cross-sectional study aimed to investigate the correlation between umbilical cord pH and Apgar scores in high-risk pregnant mothers, focusing on the neonatal outcomes at one and five minutes post-birth. Conducted from January to December 2015 at Women's Hospital Doha, Qatar, the study included 1,057 high-risk mother-fetal pairs who underwent vaginal deliveries. Key variables were analyzed using JMP (v8) statistics software, with a statistically significant p-value defined as < 0.05. Results indicated that low birth weight, smaller gestational age, and lower Apgar scores at 1 and 5 minutes significantly increased the risk of admission to the Neonatal Intensive Care Unit (NICU). The study found a significant correlation between cord gas values and the 1-minute Apgar score; however, the 5-minute Apgar score was not significantly affected by cord gas values. In conclusion, cord blood gas analysis provides valuable information on fetal metabolic conditions at birth, with umbilical cord pH demonstrating a correlation with Apgar scores in high-risk pregnancies.

The placenta is vital in exchanging gases and nutrients between the mother and the growing fetus. It is the interface between maternal and fetal circulation, allowing oxygen and nutrients to diffuse across the placental membrane from the mother's arterial blood to the fetus through the umbilical vein. The fetal tissues then extract the oxygen and nutrients they need, and the resulting deoxygenated blood – containing metabolic waste products such as carbon dioxide – returns to the placenta through the umbilical arteries. The mother's lungs and kidneys eliminate these waste products from her circulation, ensuring that the venous cord blood reflects the combined effects of maternal acid-base status and placental function. In contrast, arterial cord blood reflects neonatal acid-base status[1].

In 1952, Virginia Apgar developed a scoring system to quickly and objectively assess newborns' condition during their first minutes of life and evaluate obstetric and anaesthetic practices. The Apgar score incorporates five easily measurable clinical signs: heart rate, respiratory effort, muscle tone, reflex irritability, and colour. This scoring system has since been used to assess asphyxia and predict neurological damage and vitality in neonates during their first minute of life [2].

Cord gas analysis provides objective evidence of birth asphyxia, proving more reliable than the Apgar score alone. Since acid-base status fluctuates during the perinatal period, the timing of sample collection for analysis is crucial [3]. Ideally, the sample should be obtained immediately after birth – before the baby takes its first breath – by isolating a 20-cm cord segment between two clamps. Delaying clamping by as little as 45 seconds after birth can result in significant changes in acid-base parameters [4]. The longer the delay, the more significant the change, characterized by a progressive decrease in pH and base excess and an increase in pCO2 and lactate levels, which can confound interpretation [5, 6]. Umbilical cord blood gas assessment determines the fetal metabolic condition at birth [7–10].

Previous research has suggested that neonatal complications are associated with metabolic rather than respiratory acidosis [11]. Respiratory acidosis occurs in the early stages of impaired fetal blood supply, followed by hypoxemia and hypercapnia, which reduce pH levels while maintaining a normal base excess. Prolonged hypoxia leads to anaerobic metabolism and increased base excess due to lactic acidosis [12]. Manganaro et al. [13] proposed that the 5th-minute Apgar score is helpful for immediate clinical assessment and neonatal care, as it demonstrates a high concurrence with metabolic academia. However, Anyaegbunam et al. found that 20.7% of neonates delivered with abnormal pH (< 7.20) had a normal Apgar score [14].

Although the Apgar score is a valuable tool for rapidly assessing neonates, it often poorly correlates with other indicators of intrapartum neonatal well-being. Low arterial cord pH has strong, consistent, and temporal associations with clinically significant neonatal outcomes that are biologically plausible [15]. Nevertheless, little is known about the correlation between cord gas and Apgar score. This study aims to establish the correlation between umbilical cord pH and Apgar scores in high-risk pregnant mothers at one and five minutes.

This prospective cross-sectional study occurred from January to December 2015 at the Women's Hospital in Doha, Qatar, the nation's largest maternity hospital, averaging approximately 17,000 deliveries annually. The Medical Research Centre's Research Ethics Committee approved the study.

The study at the Women's Hospital in Doha, Qatar, involved high-risk mothers who delivered vaginally. The study population excluded women who underwent cesarean sections. High-risk pregnancies were defined based on various criteria, including Pregnant mother at risk of delivering a neonate with birth asphyxia, Severe intrauterine growth restriction, Multifetal gestations, Intrapartum fever, Maternal thyroid disease, Breech deliveries, Preterm births, Births complicated by meconium staining, Abnormal fetal heart rate pattern, Instrumental delivery, Antepartum haemorrhage, and Apgar score at 5 minutes < 7

All women in labour were monitored using an electronic fetal heart rate monitor. Immediately after vaginal delivery, umbilical cords were clamped at both ends, and arterial and venous blood samples were anaerobically collected in pre-heparinized insulin syringes. PH and base excess measurements were taken at 37°C using a pH gas analyzer, with gas analysis completed within 30 minutes of sampling. A trained physician assessed Apgar scores in the 1st and 5th minute after birth.

All resuscitated babies were transferred to the Neonatal Intensive Care Unit (NICU) for post-resuscitation care. Fetal distress was defined by an umbilical cord pH ≤ 7 and a base excess (BE) ≤ -7.

Maternal demographic data (e.g., parity, illness, nationality) and neonatal data (e.g., gestational age, birth weight, Apgar score, and need for resuscitation) were collected. NICU admissions were documented using standardized data collection sheets filled in by labour room nurses. The sheets captured maternal information, including parity, illness, nationality, arterial and venous cord gas measurements, gestational age, birth weight, one-and-five-minute Apgar scores, and whether the newborn was admitted to intensive care. The sample size was calculated from 1,061 high-risk mother-fetal pair cases.

STATISTICAL ANALYSES

The JMP (v8) statistics software package was the principle statistical and data-management software used throughout the data-analysis phase of the study. The analyses were focused on (a) providing descriptive statistics for the key variables and (b) Illustrating the relationships between different relevant factors (using the Chi-Square Test, Fisher’s Exact Test, Wilcoxon Test and the t-Test (unequal and unequal variances). A statistically-significant p-value was defined to be < 0.05.

The variables used in this study are mostly nominal so proportions were used to display most of the results.

After analyzing the study's results, taking into account the demographic and clinical characteristics of the high-risk pregnant mothers, their newborns' umbilical cord gas parameters, and the Apgar scores at one and five minutes, we were able to determine the correlation between these factors using appropriate statistical methods like linear regression and Pearson's correlation coefficient.

The study's results were analyzed, considering the demographic and clinical characteristics of the high-risk pregnant mothers, their newborns' umbilical cord gas parameters, and the Apgar scores at one and five minutes. The correlation between these factors was determined using appropriate statistical methods, such as linear regression and Pearson's correlation coefficient.

This study aimed to analyze the differences in maternal and neonatal outcomes between Qatari and non-Qatari women and explore factors that may contribute to neonatal intensive care unit (NICU) admission. The sample included 1,026 women, with 294 (28.6%) being Qatari and 732 (71.4%) being non-Qatari.

An analysis of the population descriptive statistics by nationality (Table 1) revealed significant differences between Qatari and non-Qatari women in terms of gravidity (p=0.0006) and parity (p=0.0004), with Qatari women having a higher proportion of gravid and parity than non-Qatari women. However, there was no significant difference in the proportion of abortion between the two groups (p=0.179). The mode of delivery also showed no significant difference between Qatari and non-Qatari women (p=0.0819).

The mean birth weight, gestational age, arterial pH (APH), arterial base excess (ABE), venous pH (VPH), and venous base excess (VBE) showed no significant differences between Qatari and non-Qatari women. Apgar scores at 1 and 5 minutes and admission to the NICU also showed no significant differences between the two groups.

Table 2 analyzes the NICU admission statistics by nationality. There were no significant differences between Qatari and non-Qatari women regarding gravidity, parity, abortion, mode of delivery, birth weight, gestational age, APH, ABE, VPH, VBE, and Apgar scores at 1 and 5 minutes.

Table 3 focused on the correlation between arterial and venous cord pH, base excess, and NICU admission. A significant correlation was found between arterial pH (p=0.0127) and venous pH (p=0.0523) with NICU admission. However, there was no significant correlation between arterial and venous base excess and NICU admission.

Table 4 compares the population characteristics of NICU admits and non-admits. Significant differences were found in birth weight (p<0.0001), gestational age (p<0.0001), Apgar scores at 1 minute (p<0.0001), and 5 minutes (p<0.0001). No significant differences were observed in gravidity, parity, abortion, mode of delivery, APH, ABE, VPH, and VBE between the two groups.

Tables 5 and 6 analyzed the correlation between Apgar scores at 1 and 5 minutes and arterial and venous cord pH and base excess. A significant correlation was found between 1-minute Apgar scores and arterial pH (p=0.0015), arterial base excess (p<0.0001), venous pH (p=0.0051), and venous base excess (p<0.0001). However, no significant correlation was found between 5-minute Apgar scores and arterial and venous cord pH and base excess.

Table 7 presents the logistic regression results for NICU admission. The model included gravidity, parity, abortion, APH, ABE, VPH, and VBE as independent variables. Among these, arterial pH showed a significant association with NICU admission (p=0.0252), while other variables did not show significant associations.

In conclusion, this study found significant differences between Qatari and non-Qatari women in gravidity and parity but not in other maternal and neonatal outcomes. Arterial pH was significantly associated with NICU admission, while other factors showed no significant associations.

The Apgar score is universally used for fetal assessment at birth. In contrast, the collection of fetal cord blood gases is performed commonly in high-risk situations or in the setting of Apgar scores of < 7, which is a less standardized approach. It has been well-established that neonatal academia at the time of delivery can result in significant neonatal morbidity and death. Because of this association, knowledge of the fetal acid-base status and detection of acidemia at the time of delivery can serve as a sensitive and valuable component in assessing a neonate's risk. Umbilical cord blood gas analysis is an accurate and validated tool for assessing neonatal acidemia during delivery. Because the collection of fetal cord blood gases is not a standardized practice, it is possible that, with such a varied approach, some cases of neonatal acidemia are not detected, particularly in the setting of reassuring Apgar scores.

Adverse outcomes can arise from neonatal acidosis, potentially causing disruptions to the newborn's adjustment to extra uterine life. In the literature, various values of acid-base balance and umbilical blood gas parameters are quoted as the borderline between normal and pathological [8]. The 26th Royal College of Obstetricians and Gynecologists" Study Group on Intrapartum Fetal Surveillance (1993) recommended measuring the acid-base status of the umbilical artery and vein cord blood after delivery as "a measure of the fetal response to labour" [3].

Cord arterial blood typically reflects fetal acid-base balance; hence, it has a lower pH and pO2 and a higher pCO2 than venous blood, which reflects a combination of maternal acid-base status and placental function [1].

Current data suggest that umbilical arterial pH analysis is the most sensitive diagnostic indicator of birth asphyxia, as in our study. Essential criteria for diagnosing birth asphyxia include metabolic acidosis (pH < 7.0 and base deficit = 12 mmol/L) in arterial cord blood. However, whether umbilical cord blood gas analysis should be performed selectively or at all deliveries is still being determined. Although many investigators believe that the universal use of cord gas data can improve neonatal outcomes, no studies have evaluated this contention [2].

It has since become widely accepted that umbilical cord blood gas analysis can provide important information about the infant's past, present and possibly future condition. Umbilical cord blood gas analysis is now recommended in all high-risk deliveries by the British and American Colleges of Obstetrics and Gynecology (3, 4). In some centres, it is practiced routinely following all deliveries. Low cord pH in vigorous infants at birth and free of cardiopulmonary compromise does not indicate an increased risk of adverse outcomes (5). A good blood gas in a depressed newborn should alert the neonatologist to search more diligently for other causes of neonatal depression like sepsis, trauma or congenital abnormalities (6). Considerable effort has been spent determining risk factors and intrapartum asphyxia's role in adverse neonatal outcomes (7). Based on different studies, the mean values of umbilical cord blood pH range from 7.25–7.28 (8). A baby with abnormal umbilical cord pH does not always present with poor outcomes [9].

As in our study, the obstetric team should analyze paired arterial and venous cord blood samples in all high-risk deliveries. Any cord pH = 7.1 should be recorded as a critical incident and be reported by the obstetric team to the NICU team immediately so the management plan was initiated.

In this study, we aimed to investigate the relationship between umbilical cord blood gas analysis, Apgar scores, and neonatal outcomes in a high-risk population in Qatar. Our findings provide valuable insights into the clinical utility of cord blood gas analysis and its potential role in identifying neonates at risk of adverse outcomes.

In addition, a significant relationship between Apgar score and umbilical cord pH was reported in previous studies (4, 10). Notably, this relationship was seen to be more remarkable in high-risk pregnancies (11). We could not decide about being high-risk or low-risk because the low risk was not scored in our study population. Route of delivery (SVD or C-section) had no significant impact on the first-minute Apgar in our study. In a study by Raafati et al. (Tehran, 2006), no significant relationship was found between the delivery route and the umbilical cord blood gas (12). However, in another study by Kaveh et al. in Tehran (2004), Cesarean section and low Apgar score significantly correlated with acidemia (13–15). These differences could be attributed to the emergency need for a C-section or inducing regional or general anesthesia. Our study included only the babies born via the vaginal route. However, instrumental vaginal deliveries did not impact the abnormal cord gas or constitute any significant risk for NICU admission or Apgar score.

Our study included 1,057 high-risk cases, of which 15.3% were identified as severe based on cord blood gas values. This group had a significantly higher rate of NICU admissions than those with normal cord blood gas values. We found that lower birth weight, smaller gestational age, and lower Apgar scores at 1 and 5 minutes were significantly associated with NICU admission, which aligns with other studies [16–18].

When examining the relationship between Apgar scores and cord blood gas values, we observed statistically significant differences for all comparisons, particularly when comparing these values with the 1-minute Apgar score. However, the 5-minute Apgar score was not significantly affected by the cord blood gas values, whether arterial or venous, which was in line with previous studies [19].

Our results align with previous studies demonstrating the value of umbilical cord blood gas analysis in identifying neonates at risk of adverse outcomes. Umbilical arterial pH analysis is the most sensitive diagnostic indicator of birth asphyxia, and various professional organizations have recommended its use for high-risk deliveries. However, there is still debate over whether cord blood gas analysis should be performed universally or selectively.

We performed subgroup analyses to identify specific population subgroups that may have exhibited more robust or weaker correlations between cord gas parameters and Apgar scores. These subgroups included mothers with different risk factors, neonates with varying degrees of birth asphyxia, and those requiring different levels of postnatal care. We found a strong correlation between cord gas parameters and Apgar scores, but this correlation varied across different subgroups. For instance, mothers with certain risk factors like hypertension and diabetes exhibited weaker correlations, while neonates with severe birth asphyxia had stronger correlations. These findings can help healthcare providers tailor their care and interventions to improve outcomes for high-risk pregnant mothers and newborns.

Some risk factors for fetal acidosis identified in the literature include prolonged labour, uterine hyper stimulation, twin pregnancy, spinal and general anaesthesia, placental abruption, placental infarction, chorioamnionitis, and true knots or acute cord compression. The generally accepted cut-off value for pathological acidosis is umbilical arterial pH ≤ 7.0, which has been associated with a higher risk of seizures, moderate to severe hypoxic-ischemic encephalopathy (HIE), and cerebral palsy[16].

This study highlights the importance of birth weight, gestational age, and 1-minute Apgar scores as significant predictors of NICU admission in high-risk deliveries. These findings can inform clinical practices and guide targeted interventions to reduce the need for NICU admission and improve neonatal outcomes.

It is worth noting that there are some limitations to our study. For example, we did not score the risk of the study population, and the rates of preeclampsia and diabetes were low. Furthermore, our study population was limited to high-risk cases in Qatar, which may limit the generalizability of our findings to other populations.

Despite these limitations, our study adds to the growing body of evidence supporting umbilical cord blood gas analysis in high-risk pregnancies to identify neonates at risk of adverse outcomes. Our findings highlight the importance of considering cord blood gas values in conjunction with Apgar scores when assessing neonatal risk. Further research is needed to determine the most appropriate indications for cord blood gas analysis and whether its use should be universal or selective.

In conclusion, our study demonstrates the value of umbilical cord blood gas analysis in identifying neonates at risk of adverse outcomes, particularly in high-risk populations. Our findings support the use of cord blood gas analysis in conjunction with Apgar scores when assessing neonatal risk and highlight the importance of considering birth weight, gestational age, and Apgar scores when evaluating neonates for potential adverse outcomes. Further research is needed to establish the optimal indications for cord blood gas analysis and to determine whether its use should be universal or selective.

Ethics approval and consent to participate

This research was approved by the Institutional Review Board (IRB) of the

Medical Research Center (Research proposal #11259/11), Hamad Medical

Corporation, Doha, Qatar. A waiver of informed consent was granted by the Chair of the Medical Research Center on the grounds of being a minimal risk study.

All methods were performed following the relevant guidelines and regulations. The author signs for and accepts responsibility for releasing this material on behalf of all co-authors.

Consent for publication

Not applicable.

Availability of data and materials

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Competing interests

No financial or nonfinancial benefits have been received or will be received

from any party related directly or indirectly to the subject of this article.

Funding

Not applicable

Author’s contributions

This project was a team effort with six contributors involved. Here is a summary of each contributor's contributions:

BK and NN played a crucial role in developing concepts, designing and defining intellectual content, acquiring data, editing the manuscript, and reviewing it. They also acted as guarantors for the project.

NN, YM, SA, and AA contributed to forming concepts, designing and defining intellectual content, acquiring data, preparing and editing the manuscript, and reviewing it. They also served as guarantors for the project.

NN was involved in conceptualizing, designing, defining intellectual content, conducting literature searches, acquiring data, editing the manuscript, and reviewing it. They also served as a guarantor.

BG contributed in various areas, including conducting a literature search, analyzing data statistically, editing the manuscript, reviewing it, and serving as a guarantor.

Acknowledgements

Special thanks and appreciation for the entire NICU team in WWRC who are Providing high-quality family-centered care to our newborns

Author’s information (optional)

Neonatal Intensive Care Unit (NICU), Women’s Wellness and Research

Center (WWRC), Hamad Medical Corporation (HMC), P.O. Box 3050, Doha,

Qatar

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Table 1 Population descriptive statistics by Nationality (N=1026)
	Qatari N=294	N _Q	Non-Qatari N=732	N _NQ	N-Total	P(Q vs NQ)
Gravida *	Proportion=0.70	291	Proportion =0.58	730	1021	0.0006
Parity *	Proportion=0.65	291	Proportion =0.53	730	1021	0.0004
Abortion *	Proportion=0.21	291	Proportion =0.18	730	1021	0.179
Delivery**	Proportions= 0.01/0.799/0.19	294	Proportions= 0.014/ 0.734/0.253	732	1026	0.0819
Birth weight***	Mean=3.18 (SE=0.036)	294	Mean=3.23 (SE=0.022)	732	1026	0.2231
Gestation****	Mean=38.54 (SE=0.147)	294	Mean=38.65 (SE=0.084)	738	1022	0.4443
APH*****	Mean=7.277 (SE=0.005)	287	Mean=7.259 (SE=0.0033)	720	1007	0.0044 <0.0065
ABE*****	Mean = -3.261 (SE=0.149)	281	Mean=-3.947 (SE=0.1025)	707	988	0.0001 <0.0002
VPH*****	Mean=7.298 (SE=0.005)	238	Mean=7.281 (SE=0.004)	613	851	0.0057 0.0182
VBE*****	Mean=-3.683 (SE=0.145)	233	Mean = - 4.338 (SE=0.1086)	600	833	0.0002 0.0005
Apgar 1 minute *	Proportion=0.082	294	Proportion=0.079	732	1026	0.8990
Apgar 5 minute*	Proportion=0.010	294	Proportion=0.082	729	1023	0.7217
Admission to NICU*	Proportion=0.085	294	Proportion=0.0833	732	1026	0.9015
*GRAVIDACAT : Fisher’s Exact Test (LR) --- Category A is more than 1 pregnancy; Category B is 0 or 1 pregnancies. (Note: 5 Missing Data) *PARITYCAT : Fisher’s Exact Test (LR) --- Category A is 1 or more births (gest.age>24weeks); Category B is no births. (Note: 5 Missing Data) *ABORTCAT : Fisher’s Exact Test (LR) --- Category A is 1 or more abortions; Category B is No abortions. (Note: 5 Missing Data) **DELCAT : Chi-Square (LR) --- Category A is Breech or Forceps; Category B is Normal; Category C = Vaccum (Note: 5 Missing Data) ***BIRTHWEIGHT : t-Test (Unequal Variances) ****GESTAGE : Wilcoxon Test *****APH/ABE/VPH/VBE : Upper p-value is t-Test (unequal variances) & Lower p-value is Wilcoxon Test *APGAR1SEVERE : Fisher’s Exact Test (LR) --- Category A is <=7 Category B is >= 7 APGAR5SEVERE : Fisher’s Exact Test (LR) --- Category A is <=7 Category B is >= 7* ADMITNICU : Fisher’s Exact Test (LR) --- Category A is <=7 Category B is >= 7*

TABLE 2: NICU ADMITS-STATISTICS BY NATIONALITY (N = 86)
VARIABLE	QATARI (N=25)	NQ	NON-QATARI (N=61)	NNQ	N TOTAL	p(Q -v- NQ)
GRAVIDA CAT (1 or 2)*	Proportion is 0.75	24	Proportion 0.59	61	85	0.2145
PARITY CAT (1 or 2)*	Proportion is 0.58	24	Proportion is 0.51	61	85	0.6317
ABORT CAT (1 or 2)*	Proportion is 0.13	24	Proportion is 0.20	61	85	0.5399
DELCAT**	Numbers 1 / 20 / 4	25	Numbers 2 / 48 / 11	61	86	0.9645
BIRTHWEIGHT***	Mean = 2.20 (SE=0.181)	25	Mean = 2.53 (SE=0.116)	61	86	0.1240
GESTAGE****	Mean = 33.96 (SE=0.857)	25	Mean = 35.42 (SE=0.603)	61	86	0.1682
APH*****	Mean = 7.294 (SE=0.0187)	24	Mean = 7.245 (SE=0.0176)	59	83	0.0595 0.1438
ABE*****	Mean = -3.075 (SE=0.534)	24	Mean = -4.644 (SE=0.524)	57	81	0.0399 0.1489
VPH*****	Mean = 7.316 (SE=0.020)	21	Mean = 7.261 (SE=0.020)	46	67	0.0560 0.2561
VBE*****	Mean = -3.562 (SE=0.507)	21	Mean = -4.925 (SE=0.571)	44	65	0.0794 0.2276
APGAR1SEVERE (<=7/>=7)*	Proportion (<=6) = 0.120	25	Proportion (<=6) = 0.049	25	86	0.3507
APGAR5SEVERE (<=7/>=7)*	Proportion (<=6) = 0.440	61	Proportion (<=6) = 0.3443	61	86	0.4651

Table 3 . Admission To NICU
		No admission		Admission	Totals		P=0.0127 Fisher Exact Test
Arterial PH >7		916	79		995
Arterial PH ≤7		8	4		12
*Totals*		924	83		1007
Arterial BE > -7		794	65		859		P=0.0827 Fisher Exact Test
Arterial BE ≤7		133	16		129
*Totals*		907	81		988
Venous PH >7		781	65		846		P=0.0523 Fisher Exact Test
Venous PH ≤7		3	2		5
*Totals*		784	67		851
Venous BE >-7	673			52		725	P=0.0845 Fisher Exact Test
Venous BE ≤7	95			13		108
*Totals*	768			65		833

TABLE 4: POPULATION DESCRIPTIVE STATISTICS BY NICU-ADMITS (N=1,026)
	NICU ADMITS (N=85)	NICU NON-ADMITS (N=936)	N	p
GRAVIDA (1/>1)*	Proportion = 0.64	Proportion = 0.62	1,021	0.5690
PARITY (0/>0)*	Proportion = 0.53	Proportion = 0.56	1,021	0.6486
ABORTION (0/>0)*	Proportion = 0.18	Proportion = 0.18	1.021	1.0000
DELIVERY**	Proportions = 0.04 / 0.80 / 0.17 [NTOT=3+68+15=86]	Proportions = 0.01 / 0.75 / 0.24 [NTOT=10+704+226=940]	1,026	0.1134
BIRTHWEIGHT***	Mean = 2.430 (SE=0.098)	Mean = 3.284 (SE=0.016)	1,026	<0.0001
GESTAGE***	Mean = 35.00 (SE=0.498)	Mean = 38.95 (SE=0.054)	1,022	<0.0001
APH****	Mean = 7.260 (SE=0.014)	Mean = 7.265 (SE=0.003)	1,007	0.3557 0.6247
ABE****	Mean = -4.179 (SE=0.4076)	Mean = -3.714 (SE=0.085)	988	0.1334 0.6518
VPH****	Mean = 7.278 (SE=0.155)	Mean = 7.287 (SE=0.081)	851	0.2915 0.6122
VBE****	Mean = -4.487 (SE=0.425)	Mean = -4.127 (SE=0.089)	833	0.8642 0.4123
APGAR 1 SEVERE (<=7/>=7)*	Proportion (>=7) = 0.628	Proportion (>=7) = 0.947	1,026	<0.0001
APGAR 5 SEVERE (<=7/>=7)*	Proportion (>=7) = 0.930	Proportion (>=7) = 0.997	1,023	<0.0001
NATIONALITY	Proportion = 0.290	Proportion = 0.286	1,026	0.9015

*ADMITNICU : Fisher’s Exact Test (LR) --- Category A is <=7 Category B is >= 7

GRAVIDACAT : Fisher’s Exact Test (LR) --- Category A is more than 1 pregnancy; Category B is 0 or 1 pregnancies. (Note: 5 Missing Data)

*PARITYCAT : Fisher’s Exact Test (LR) --- Category A is 1 or more births (gest.age>24weeks); Category B is no births. (Note: 5 Missing Data)

*ABORTCAT : Fisher’s Exact Test (LR) --- Category A is 1 or more abortions; Category B is No abortions. (Note: 5 Missing Data)

**DELCAT : Chi-Square (LR) --- Category A is Breech or Forceps; Category B is Normal; Category C = Vaccum (Note: 5 Missing Data)

***BIRTHWEIGHT : t-Test (Unequal Variances)

****GESTAGE : Wilcoxon Test

*****APH/ABE/VPH/VBE : Upper p-value is t-Test (unequal variances) & Lower p-value is Wilcoxon Test

*APGAR1SEVERE : Fisher’s Exact Test (LR) --- Category A is <=7 Category B is >= 7

*APGAR5SEVERE : Fisher’s Exact Test (LR) --- Category A is <=7 Category B is >= 7

Table 5. Correlation between Apgar Score 1 minute and Arterial and venous Cord PH & BE
	Apgar score >6	Apgar score ≤6	Totals	P=0.0015 Fisher Exact Test
Arterial PH >7	919	76	995
Arterial PH ≤7	7	5	12
*Totals*	926	81	1007
Arterial BE >7	809	50	859	P<0.0001 Fisher Exact Test
Arterial BE ≤7	99	30	129
*Totals*	908	80	988
Venous PH >7	777	69	846	P=0.0051 Fisher Exact Test
Venous PH ≤7	2	3	5
*Totals*	779	72	851
Venous BE >7	679	46	725	P<0.0001 Fisher Exact Test
Venous BE ≤7	83	25	108
*Totals*	762	71	833

Table 6. Correlation between Apgar Score 5 minute and Arterial and venous Cord PH & BE
	Apgar score >6	Apgar score ≤6	Totals	P=1.0 Fisher Exact Test
Arterial PH >7	983	9	992
Arterial PH ≤7	12	0	12
*Totals*	995	9	1004
Arterial BE >7	849	7	856	P=0.3339 Fisher Exact Test
Arterial BE ≤7	127	2	129
*Totals*	976	9	985
Venous PH >7	834	9	843	P=1.0 Fisher Exact Test
Venous PH ≤7	5	0	5
*Totals*	839	9	848
Venous BE >7	714	8	722	P=1.0 Fisher Exact Test
Venous BE ≤7	107	1	108
*Totals*	821	9	830

TABLE 7: LOGISTIC REGRESSION RESULTS FOR ADMITNICU (NTOT = 1,026)
TERM	ESTIMATE	STD. ERROR	CHI-SQUARE	P-VALUE
Intercept	-39.1080	23.3620	2.8000	0.0941
GRAVIDACAT[1]	-0.5426	0.3463	2.4600	0.1171
PARITYCAT[1]	0.1344	0.3263	0.1700	0.6803
ABORTYN[1]	0.4927	0.2776	3.1500	0.0759
APH	2.7531	3.1743	0.7500	0.3858
ABE	-0.0931	0.1520	0.3800	0.5400
VPH	0.8759	3.1895	0.0800	0.7836
VBE	0.0549	0.1597	0.1200	0.7310
DELCAT[BreechForc]	-1.4053	2.4050	0.3400	0.5590
DELCAT[Normal]	-0.2034	0.4197	0.2300	0.6280
BIRTHWEIGHT	1.0823	0.3729	8.4300	0.0037
GESTAGE	0.3477	0.0770	20.4200	<.0001
APGAR1SEVERE[0]	1.0131	0.2318	19.1000	<.0001
APGAR5SEVERE[0]	0.0852	0.6361	0.0200	0.8935

No competing interests reported.

Evaluating the Link between Cord Gas Parameters and Apgar Scores in High-Risk Pregnancies: Insights from a One-Year Study in Qatar

Status:

Version 1

Abstract

Introduction

Study Design and Methods

STATISTICAL ANALYSES

Results

Discussion

Declarations

References

Tables

Additional Declarations

Status:

Version 1