The effect of labor and delivery mode on electrocortical and brainstem autonomic function during neonatal transition.

Delivery of the newborn occurs either vaginally or via caesarean section. It is not known whether the mode of delivery and exposure to labor affects early autonomic nervous system (ANS) function, as measured by heart rate variability (HRV), or cortical electroencephalogram (EEG) activity. The objective of the study was to determine if autonomic function in newborns differs by mode of delivery. Simultaneous recording of EEG and electrocardiogram were collected in low-risk term newborns at <72 hours of age to measure HRV, the asymmetry index, and EEG power. Newborns were compared by delivery type: vaginal delivery (VD), cesarean section (CS) after labor (L-CS), or elective CS (E-CS). Quantile Regression controlled for gestational age, postnatal age, and percent active states. One hundred and eighteen newborns were studied at 25.2 (11.4) hours of age. Sixty-two (52.5%) were born by VD, 22 by L-CS (18.6%), and 34 by E-CS (28.8%). HRV metrics didn't differ by delivery mode. Asymmetry index was higher in L-CS compared to VD and E-CS (P = 0.03). On EEG, L-CS newborns showed lower relative gamma power compared to VD and E-CS (P = 0.005). The study found that overall ANS tone is not altered by mode of delivery in low-risk term newborns.