Introduction: Despite the high efficacy of the Apgar score to find respiratory distress, a low Apgar score doesn’t necessarily indicate fetal hypoxia-asphyxia. Umbilical Artery pH (UApH) is one the best indicator of fetal hypoxia. Therefore it’s so beneficial to consider these criteria and its relationship with Apgar score for accurate diagnosis of prenatal respiratory distress retrospectively and by which reduces the unnecessary cesarean section(CS) rate.
Methods: 162 full-term (≥259 days) neonates delivered by CS with a diagnosis of decreased fetal heart rate (FHR) were evaluated. 1-min and 5-min Apgar scores and UApH were measured. The correlation between Apgar scores with UApH and the association between UapH and Apgar with the NICU admission were evaluated. The effect of other variables including mother’s age, gravidity, gestational age, birth weight, newborn gender, and causes of decreased FHR on Apgar scores and UApH were studied as well.
Results: The most common cause of decreased FHR was fetal distress, boys had higher weight (p=0.033) and lower UApH (p=0.049) than girls. Other parameters were not different significantly between males and females. There was a positive correlation between UApH and 1-min and 5-min Apgar scores (r=0.464 and r=0.370 respectively) when controlled for birth weight (p<0.0001). The RR for NICU admission in male acidemic neonates with abnormal 1-min Apgar was 14.05(CI95%: 5.7-34.6) in comparison to females (RR=1.06, CI95%:1-1.26).
Conclusion: Mild acidemia (UApH<7.2) at least in male fetuses would be a good predictor for postnatal complications and the need for NICU admission. Future studies with more samples are suggested.