Timing of planned cesarean delivery among patients with two previous cesarean sections

Objectives: The timing of planned repeat cesarean delivery (CD) is debateful in clinical practice. Planned repeat CD is typically scheduled before the spontaneous onset of labor to minimize the risk of uterine rupture during labor and the associated risk for fetal compromise. This timing should be balanced with the potential risk of delivering an infant who could benefit from additional maturation in utero. We aim to study the influence of gestational age at the time of repeat CD on maternal and fetal complications. Study design: A population-based retrospective cohort study including all term singleton third CDs (≥ 37 weeks of gestation), between February-2020 and January-2022 at a tertiary medical center was conducted. Maternal and neonatal adverse outcomes were compared by gestational age at the time of the CD. A logistic regression models were constructed to adjust for confounders. Results: The study population included624 third CDs. Among them, two study groups were defined: 199 were at 37 + 0 to 37 + 6 weeks of gestation, and 44 were at ≥ 39 weeks of gestation at the time of delivery. 381 were at 38 + 0 to 38 + 6 weeks. Since our routine practice is to schedule elective CD at 38 + 0 to 38 + 6 weeks of gestation, we defined this group as the comparison group. In a multivariate analysis, both study groups were associated with significantly higher rates of emergent CDs after adjusting for maternal age, parity, ethnicity, premature rapture of membranes, spontaneous onset of labor and birthweight. After adjusting also for emergent CDs, CDs at 37 + 0 to 37 + 6 weeks of gestation were significantly associated with maternal and neonatal length of stay exceeding 4 days. Additionally, CDs at 37 + 0 to 37 + 6 weeks of gestation were also associated with composite of adverse neonatal and maternal outcomes. Conclusions: Our study demonstrated that scheduling third CD at 38 + 0 to 38 + 6 weeks is associated with reduced risk of emergent CD, as well as beneficial maternal and neonatal outcomes.