Outcomes of Ultrasound or Physical Examination-Indicated Cerclage according to the Degree of Cervical Dilation

Abstract

Objective: Pregnancy outcomes of individuals receiving cervical cerclage when the cervix is dilated are not well known. We sought to examine preterm birth rates after ultrasound or physical examination-indicated cerclage placement according to the degree of cervical dilation.

Study design: This was a retrospective cohort study of individuals with singleton pregnancies undergoing ultrasound or physical examination-indicated cerclage before 24^0/7 weeks of gestation from 2004 to 2018. Individuals were categorized based on the degree of cervical dilation at the time of cerclage. Our primary outcome was preterm delivery at less than 37 weeks of gestation. Multivariable logistic regression was performed to calculate adjusted odds ratios (aOR) with 95th confidence intervals (95% CI), controlling for predefined covariates.

Results: Of 147 individuals undergoing ultrasound or physical examination-indicated cerclage, 90/147 (61%) had a closed or 0.5 cm dilated cervix at the time of cerclage placement, 45/147 (31%) had a cervical dilation of 1 to 2.5 cm, and 12/147 (8%) had a cervical dilation of 3 to 4 cm at the time of placement. Individuals with a cervical dilation of 1 to 2.5 cm compared with those who had a closed cervix did not have increased odds of preterm delivery (58 vs. 42%; aOR: 1.95; 95% CI: 0.93-4.07). However, individuals with a cervical dilation of 3 to 4 cm compared with individuals who had a closed cervix had significantly increased odds of preterm delivery (75 vs. 42%; aOR: 4.33; 95% CI: 1.05-17.77).

Conclusion: The rate of preterm birth increases with increasing cervical dilation at the time of cerclage placement. However, individuals who have a cerclage placed when the cervix is 1 to 2.5 cm can achieve an outcome that is not significantly different from those who had a cerclage placed when the cervix is closed.

Key points: · Time from cerclage placement to delivery decreases as cervical dilation increases.. · Individuals 1 to 2.5 cm dilated at the time of cerclage can achieve a favorable outcome.. · A cervical dilation of ≥3 cm at cerclage placement was associated with extreme prematurity..