In-labor cesarean delivery and spontaneous preterm birth: addressing the clinical challenge.

Abstract

Evidence has identified an association between cesarean delivery performed during labor, particularly at advanced and full dilatation, and increased risk of subsequent midtrimester loss and spontaneous preterm birth. Risk is the highest after full dilatation, with reported odds ratios of up to 3.42 compared with vaginal delivery. The subset of these patients who preterm represents a particularly high-risk group, with spontaneous preterm birth that is recurrent and difficult to treat. Given the rising global rates of cesarean delivery, this issue is poised to become increasingly prevalent. Managing spontaneous preterm birth risk in women with previous in-labor cesarean delivery is an important clinical challenge. More understanding of the underlying causative mechanisms would facilitate the identification of patients most at risk. Screening guidelines vary for this cohort, and no guidance currently incorporates subsequent screening for cesarean deliveries with cervical dilatation of <10 cm. A risk prediction tool to identify which women need screening before a subsequent pregnancy would be of most use to minimize the burden on services and prevent avoidable pregnancy loss. In those who would benefit from screening, cesarean scar characteristics and position may be a useful predictive tool in subsequent pregnancies. The high failure rates of transvaginal cerclage in this cohort remain a concern, and prospective trials are needed to determine optimal intervention, including progesterone and abdominal cerclage.