Effect of maternal risk characteristics on neonatal outcome correlated to mode of delivery

This paper explores the associations among modes of delivery, maternal and perinatal outcome and risk factors of pregnancy. We examined medical birth register data of 18539 infants from 18249 deliveries admitted to ten delivery units from Feb. 1992 to Feb. 1993. After controlling the potential confounding effect of maternal and infant characteristics, the outcome measures of different modes of delivery were compared. Incidence of high risk pregnancy was 33.2% (n=6051); in this group, in comparison with vaginal delivery, cesarean section was associated with higher maternal morbidity (11.2% vs 3.4%; p<0.001), but lower neonatal morbidity and perinatal mortality (9.4% vs 28%, 0.8% vs 6.2% respectively; p<0.001). Moreover, multiple logistic regression analysis showed vaginal delivery increased the perinatal mortality (odds ratio: 4.0, 95% confidence interval: 2.5-6.2, p<0.01) and neonatal morbidity (odds ratio: 1.8, 95% confidence interval: 1.4-2.4, p<0.001) but decreased the maternal morbidity (odds ratio: 0.24, 95% confidence interval: 0.18-0.32, p<0.001). In non-high risk pregnancy (n=12198), cesarean section was also associated with higher maternal morbidity (3.7% vs 1.2%; p<0.001), but for neonatal morbidity and perinatal mortality there was no difference with different modes of delivery . In conclusion, cesarean section was associated with a better birth neonatal outcome in high risk pregnancy; however, it raised maternal morbidity without improving the neonatal outcome in non-high risk pregnancy.