Neonatal morbidity after spontaneous labor onset prior to intended cesarean delivery at term: a cohort study

Introduction: We aimed to investigate if labor onset before planned cesarean delivery (CD) affects the risk of neonatal admission, respiratory distress, or neonatal infectious morbidity.

Material and methods: Our cohort included singleton term pregnant women with intended CD who delivered at Aarhus University Hospital from 1990 to 2012. Two groups of women were identified: women with intended CD performed before labor (nonlabor CD) and women with intended CD performed after spontaneous labor onset (labor-onset CD); in both groups there was no other maternal or fetal medical indication for an immediate CD or for early-term CD scheduling. Data were stratified in early-term (37-38 weeks) and full-term (39-40 weeks) deliveries. The main outcome measures were neonatal admission, respiratory distress and neonatal infectious morbidity.

Results: Among 103 919 live births, 5071 deliveries were nonlabor CDs and 731 were labor-onset CDs. Compared to nonlabor CD, labor-onset CD was associated with similar risks of neonatal admission and respiratory distress, both at early and full term, but with a two- to three-fold increased risk of newborn septicemia or antibiotic treatment at early term. Labor onset at early term was associated with a lower risk of maternal blood loss of more than 500 mL, but with a higher risk of postoperative antibiotic treatment and endometritis.

Conclusions: Labor onset before planned CD was not associated with a decrease in neonatal respiratory morbidity, but may be associated with increased risks of neonatal infection.