Outcomes of ultrasound and physical-exam based cerclage: assessment of risk factors and the role of adjunctive progesterone in preventing preterm birth—a retrospective cohort study

Objective: To assess outcomes of ultrasound and physical examination-based cerclage performed at mid to late second trimester and to assess the potential added value of progesterone treatment combined with cerclage for preventing preterm birth. Study design: A retrospective cohort study of women who underwent cerclage in a university-affiliated tertiary medical center (2012–2018). Inclusion criteria included only ultrasound-based cerclage and physical examination-based cerclage. Women who underwent history-based cerclage or multiple gestations were excluded. Study groups were stratified by previous PTB < 37 weeks and other risk factors for PTB. Primary outcome was the incidence of preterm birth < 35 weeks of gestation. Secondary outcomes included the potential added value of progesterone treatment and neonatal outcome. Results: Sixty-nine women underwent cervical cerclage placement between 16–23 weeks of gestation. All women had short cervix (cervical length of < 25 mm) at presentation. Indications for cerclage placement included: 29% previous PTB, 32% prior cervical interventions (history of at least one D&C, hysteroscopy or cold-knife conization in the past), 22% had cervical dilatation > 1 cm at presentation, 12% due to failure of progesterone treatment defined as continued cervical shortening after 14 days of progesterone treatment, and 5% had other indications. Overall, 42 women (61%) gave birth at term. 27 women (39%) delivered prior to 37 weeks of gestation, of them, 20 women (29%) gave birth prior to 35 weeks. Overall median gestational age at delivery was 35 + 5 ± 4.7 weeks. Cervical dilatation at presentation of > 1 cm was associated with an increased risk for PTB < 35 weeks (OR 3.57, CI 1.43–30.81, p = 0.036). Previous PTB, prior cervical interventions and extent of cervical shortening at presentation did not increase the risk of PTB. Progesterone treatment in addition to cerclage did not result in a decreased risk for PTB < 35 weeks of gestation (OR 2.83, CI 0.58–13.89, p = 0.199). Conclusion: Late second trimester cerclage is a practical measure for preventing PTB in cases of asymptomatic cervical shortening. Our study did not find adjunctive benefit for progesterone treatment with physical or ultrasound-based cerclage in reducing the rate PTB.