Outcomes after periviable ultrasound-indicated cerclage

Cerclage placed for a sonographically short cervix has been shown to reduce the risk of preterm delivery in women with a history of prior preterm birth. While short cervix is traditionally placed before viability, the threshold gestational age at which viability is achieved continues to decrease, and, as a result, a larger subset of women may be ineligible to receive this potentially beneficial procedure.

To evaluate the association between obstetric outcomes and perioperative complications after placement of an ultrasound-indicated cerclage at periviability compared to placement in the previable period.

This retrospective cohort study of patients who underwent ultrasound-indicated cerclage evaluated obstetric outcomes and perioperative complications based on gestational age at cerclage placement. Ultrasound-indicated cerclage was considered to have been placed at periviability if placed at 22 to <24 weeks (exposed) and at previability if placed at 16 to <22 weeks gestational age (unexposed). The primary outcome was preterm delivery <36 weeks. Secondary outcomes included mean gestational age at delivery, preterm delivery <32 weeks, <28, and <24 weeks, preterm premature rupture of membranes (PPROM), chorioamnionitis, and perioperative complications. Adjusted analyses were performed to account for demographic and obstetric factors.

Of the 426 patients included in the analysis, 94 (22%) had cerclage placed between ≥22 weeks to <24 weeks, while 332 (78%) had cerclage placed at <22 weeks. On univariate analysis, women who had a periviable cerclage placed were less likely to have a recurrent preterm delivery <36 weeks compared to women with previable cerclage placement (26.6 versus 38.3%, respectively, p = .04). The adjusted model did not demonstrate a significant difference in risk for preterm delivery <36 weeks associated with periviable versus previable cerclage (odds ratio 0.66, 95%CI 0.37-1.17). Secondary outcomes were similar between the previable and periviable groups, including mean gestational age at delivery (35.1 versus 36.2 weeks, respectively, p = .08) and preterm delivery before 32-week gestation (20.7 versus 13.8%, respectively, p = .17). Intraoperative and postoperative complications were rare and rates were similar between groups.

Obstetric outcomes between patients receiving periviable and previable cerclage are similar. Ultrasound-indicated cerclage placement is associated with a relatively low rate of complications. Given the evidence supporting benefit of cerclage for women with short ultrasound cervical length and prior preterm birth, our findings demonstrate that benefits of placement at ≥22 weeks to <24 weeks may outweigh risks.