Cerclage in singleton gestations with an extremely short cervix (≤10 mm) and no history of spontaneous preterm birth

Data regarding the efficacy of a cervical cerclage for preterm birth prevention in patients with a short cervix and no history of spontaneous preterm birth are limited and inconclusive.

This study aimed to determine whether cervical cerclage is associated with an increased time interval to delivery in asymptomatic patients with singleton pregnancies with an extremely short cervical length (≤10 mm) and no history of spontaneous preterm birth.

This was a multicenter retrospective cohort study of asymptomatic patients with singleton pregnancies with a cervical length of ≤10 mm between 16 and 23 weeks' gestation from January 2014 to December 2019. Patients with previous spontaneous preterm birth, symptoms of preterm labor, cervical dilation of >1 cm, pessary, major fetal structural malformations, or missing data were excluded from the study. The primary outcome of time interval from diagnosis to delivery was compared between those who had a cervical cerclage after diagnosis and those who did not. The secondary outcomes included gestational age at delivery and adverse neonatal outcomes. Moreover, a subgroup analysis of all outcomes in patients already being treated with vaginal progesterone in each group was performed. Statistical analysis included chi-square and Wilcoxon rank-sum tests and a multivariate Cox proportional hazard regression for time interval to delivery.

Of the 90 patients included in the study, 52 (57.8%) had cervical cerclage, of which 35 (67.3%) were already being treated with progesterone. Moreover, 38 patients (42.2%) did not have cervical cerclage, of which 21 (55.3%) were already being treated with progesterone. Patients in the cervical cerclage group had an earlier gestational age (21.0 vs 22.0 weeks' gestation; P≤.001) and shorter cervical length (5 vs 7 mm; P=.002) at the diagnosis of a short cervix (cervical length≤10 mm) than those who did not have a cerclage. Cervical cerclage was associated with a longer time interval to delivery (17.0 vs 15.0 weeks; P=.02) and lower hazard of earlier delivery after diagnosis (adjusted hazard ratio, 0.61; 95% confidence interval, 0.38-0.99; P=.04) than no cerclage, after accounting for gestational age and cervical length at diagnosis. In patients already treated with progesterone, cervical cerclage was also associated with a longer time interval to delivery (17.0 vs 13.1 weeks; P=.01) and a lower hazard of earlier delivery after diagnosis (adjusted hazard ratio, 0.49; 95% confidence interval, 0.27-0.87; P=.02) compared to those with no cerclage. Late preterm birth was less common in patients with a cervical cerclage compared with those with no cervical cerclage (11.5% vs 31.6%; P=.03).

Cervical cerclage should be considered in asymptomatic patients with an extremely short cervical length (≤10 mm) and no history of spontaneous preterm birth.