(912) Interval to ultrasound-indicated cerclage placement and delivery timing in patients with prior preterm birth

Patients with a history of preterm birth and a cervical length less than 25mm benefit from cerclage to prevent recurrence. The urgency of cerclage placement after diagnosing a short cervix varies. This study aimed to determine if the time from diagnosis to cerclage placement affects delivery timing.

Study Design:

This was a retrospective cohort study of all patients with a history of preterm birth who received an ultrasound-indicated cerclage in a subsequent pregnancy from 2018-2023 within a large health system in New York. The primary exposure was time interval from diagnosis of short cervix ( < 25mm) to cerclage placement. The primary outcome was gestational age at delivery. Outcomes were compared using a linear mixed model regression analysis and were then adjusted for obesity, gestational age at diagnosis of a short cervix and cervical length at diagnosis.

Results:

A total of 49 patients were included for analysis. The mean time interval for cerclage placement after diagnosis was 5.9 days and mean gestational age at cerclage placement was 19.0 ± 2.6 weeks. The mean cervical length on ultrasound at time of diagnosis of a short cervix was 1.8 ± 0.6 cm. The mean gestational age at delivery was 36.6 ± 3.3 weeks. Overall, for each additional day that elapsed between diagnosis of a short cervix and cerclage placement, pregnancy on average was shortened by 1.6 days (P=0.01) (figure 1).

Conclusion:

For patients with a history of preterm birth receiving an ultrasound-indicated cerclage, earlier placement after diagnosis of short cervix significantly benefited pregnancy length, resulting in a later gestational age at delivery.