Vaginal delivery for early preterm foetuses presenting head first, or vertex presentation, had a high rate of success with no difference in neonatal mortality compared to caesarean delivery, a new study, led by Indian origin researcher, has revealed.
For breech births, however, the failure rate of vaginal delivery was high and planned caesarean delivery was associated with significantly lower neonatal mortality.
“Selecting a route of delivery at less than 32 weeks’ gestation is a difficult clinical decision given the high rate of infant mortality and morbidity as well as the maternal risks associated with caesarean delivery,” says lead investigator Uma M. Reddy, MD, MPH, of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD.
“For vertex-presenting foetuses less than 32 weeks’ gestation, we saw no improvement in neonatal mortality with a planned caesarean delivery,” she said.
Dr. Reddy and her colleagues used data from the Consortium on Safe Labor (CSL), a study conducted by the Eunice Kennedy Shriver National Institute of Child Health and Development, National Institutes of Health.
The investigators first categorized the indications for preterm delivery: preterm labour, preterm premature rupture of membranes (PPROM), or fetal/maternal issues such as preeclampsia, placental abruption, or severe maternal medical disease.
Maternal or foetal indications were responsible for 45.7 percent of early preterm deliveries, PPROM for 37.7 percent, and preterm labour for 16.6 percent.
Preeclampsia and major congenital anomalies were the leading contributors to indicated early preterm births. The study then evaluated 2,906 singleton pregnancies between 24 0/7 weeks and 31 6/7 weeks eligible for either route of delivery. Attempted vaginal delivery was compared to planned caesarean delivery.
Data were analysed based on gestational age blocks: 24 0/7 to 27 6/7 weeks and 28 0/8 to 31 67 weeks, based on the fact that the highest rates of neonatal mortality and morbidity occur 24 0/7 to 27 6/7 weeks.
Attempting vaginal delivery with vertex presentation at 24 0/7 to 27 6/7 weeks of gestation did not significantly affect neonatal mortality. More than 80 percent of the attempted vaginal births were successful.
However, if the foetal presentation was breech, the majority of the deliveries were by planned caesarean delivery, and only 27.6 percent of attempted vaginal deliveries were successful.
Findings in the 28 0/7 to 31 6/7 weeks’ gestation also differed by presentation. If the foetal presentation was vertex, the majority of attempted vaginal deliveries succeeded and there was no difference in the neonatal mortality rate compared with planned caesarean delivery.
For breech-presenting foetuses, neonatal mortality was 6 percent for vaginal deliveries compared to 1.5 percent of the caesarean deliveries.
The study was recently published in the American Journal of Obstetrics and Gynaecology.