Introduction: ACOG recommends performing repeat elective cesarean delivery (CD) at 39 weeks in women with one previous cesarean delivery. However there is uncertainty regarding timing of delivery for women with two or more previous CD. Our aim was to examine maternal and neonatal outcomes of elective CD at 37+0 to 40+6 weeks compared with pregnancy continuation in women with at least two previous CD.
Methods: A retrospective study of all women with at least two previous CD who delivered at term in Ontario, Canada between 4/2012 and 3/2017. Maternal and neonatal characteristics and outcomes were obtained from linked provincial and national databases. Multiple gestations and pregnancies with major fetal anomalies were excluded. Each gestational week of elective CD was compared with ongoing pregnancy, culminating in CD in labor, indicated CD not in labor or vaginal delivery. The primary outcome was a composite of adverse maternal outcomes. Secondary outcomes were composite adverse neonatal outcomes.
Results: 17,207 women were eligible for analysis. Elective CD from 39 weeks onwards was associated with the lowest adjusted risk of maternal composite adverse outcome (2.4% vs 6.9%, OR 0.36, 95% CI 0.2-0.65). This was primarily driven by lower rates of preeclampsia (0.4% vs 1.7%, p<0.004), gestational hypertension (1.6% vs 3.6%, p=0.005) and uterine rupture, occurring in 1.7% of ongoing pregnancies. Elective CD at 37 weeks was associated with an increased risk of neonatal composite adverse outcome compared with ongoing pregnancies (OR 1.51, 95% CI 1.19-1.92). This risk was only decreased with elective CD at 39-39+6 weeks (10.3% vs 18.2%, OR 0.64, 95% CI 0.44-0.94).
Conclusion: In women with two or more prior cesareans, the lowest rates of adverse maternal and neonatal outcomes were observed with elective CD between 39 and 39+6 weeks of gestation. This needs to be balanced against the risk of unplanned delivery prior to this gestational age.
Nir Melamed– MFM Specialist, Sunnybrook Health Sciences Centre, University of Toronto
Jon Barrett– Chief of Maternal-Fetal Medicine at Sunnybrook Health Sciences Centre, Sunnybrook Health Sciences Centre, University of Toronto
Howard berger– Head, Maternal and Fetal Medicine, St Michael's Hospital