Adverse outcomes in early term versus full-term deliveries among higher-order cesarean births

Objective: In an attempt to avoid emergency deliveries of women with multiple prior scars, providers may choose to schedule those repeat cesarean births prior to 39 weeks. Our primary goal was to compare rates of assisted ventilation use between neonates with early term (37°-38⁶ weeks) and full-term (39°-39⁶ weeks) deliveries among women with three or more prior cesarean births.

Methods: A retrospective cohort study of women with three or more previous cesarean births. The study group consisted of women who delivered at early term (37°-38⁶ weeks). The control group consisted of women who delivered at full term (39°-39⁶ weeks gestation). Women with a history of pre-gestational diabetes, gestational hypertension and chronic hypertension were excluded. Data were extracted from the 2017 United States Natality database. Characteristics were compared between groups for potential confounders. Primary outcome, neonatal assisted ventilation use greater than 6 h, and other secondary outcomes (including immediate assisted ventilation in the neonate and uterine rupture) were compared between groups. Multivariable logistic regression analyses were performed to adjust for potential confounding factors between groups.

Results: A total of 28,584 women with three or more prior cesarean births were included. There were 12,391 women who delivered at early term, and 16,193 who delivered at full term. Neonates born from women who delivered at early term had an increased risk of assisted ventilation use greater than 6 h compared with neonates who delivered at full term (assisted ventilation greater than 6 h, adjusted odds ratio (aOR) 2.08, 95% confidence interval (CI) [1.59-2.73]). Neonates delivered at early term were also more likely to need immediate ventilation use than were neonates delivered at full term (aOR 1.52, 95% CI [1.33-1.73]). Women who delivered at early term had a higher rate of uterine rupture compared with women who delivered at full term (OR 5.67, 95% CI [2.33-13.79]).

Conclusion: Higher order cesarean births performed early term had an increased risk of neonatal assisted ventilation use greater than 6 h compared with full-term births. These results argue against delivering women with multiple prior uterine scars before term in an attempt to avoid emergency sections.