Objective: The purpose of this study was to examine the influence of labor on extremely-low-birth-weight infants who were born by cesarean delivery with reference to neonatal and neurodevelopmental outcomes. We hypothesized that infants who are born by cesarean delivery without labor will have better outcomes than those infants who are born by cesarean delivery with labor.

Study design: This was a retrospective cohort study of extremely-low-birth-weight infants (birth weight, 401-1000 g) who were born by cesarean delivery and cared for in the National Institute for Child Health and Human Development Neonatal Network, during calendar years 1995 to 1997. A total of 1606 extremely-low-birth-weight infants were born by cesarean delivery and survived to discharge. Of these, 1273 infants (80.8%) were examined in the network follow-up clinics at 18 to 22 months of corrected age and had a complete data set (667 infants were born without labor, 606 infants were born with labor). Outcome variables that were examined include intraventricular hemorrhage grade 3 to 4, periventricular leukomalacia, and neurodevelopmental impairment.

Results: Mothers in the cesarean delivery without labor group were older (P<.001), more likely to be married (P<.05), less likely to be supported by Medicaid (P<.01), more likely to have preeclampsia/hypertension (P<.001), more likely to receive prenatal steroids (P<.005), and less likely to have received antibiotics (P<.001). Infants who were born by cesarean delivery without labor had higher gestational age (P<.001), lower birth weight (P<.01), and were less likely to be outborn (P<.001). By univariate analysis, infants who were born by cesarean delivery with labor had a higher incidence of grade 3 to 4 intraventricular hemorrhage (23.3% vs 12.1%, P<.001), periventricular leukomalacia (8.5% vs 4.7%, P<.02), and neurodevelopmental impairment (41.7% vs 34.6%, P<.02). Logistic regression analysis that controlled for all maternal and neonatal demographic and clinical variables that were statistically associated with labor or no labor revealed that the significant differences in grade 3 to 4 intraventricular hemorrhage, periventricular leukomalacia, and neurodevelopmental impairment were no longer evident.

Conclusion: In extremely-low-birth-weight infants who were born by cesarean delivery and after control for other risk factors, labor does not appear to play a significant role in adverse neonatal outcomes and neurodevelopmental impairment at 18 to 22 months of corrected age.