Two-stitch versus one-stitch cervical cerclage in women with high risk for preterm birth: a stratified exploratory randomized controlled trial in China

TL;DR

This study compared two surgical techniques for preventing early birth in high-risk pregnancies in China, finding no major difference in most cases but a hint that one method might help prevent very early births.

Contribution

The study is the first stratified RCT comparing two-stitch and one-stitch cerclage techniques in both therapeutic and emergency settings for preterm birth prevention.

Findings

In therapeutic cerclage, two-stitch did not reduce preterm birth before 34 weeks compared to one-stitch.

Emergency cerclage with two-stitch was linked to fewer births before 28 weeks, though not for the primary outcome.

Neonatal survival rates were similar between groups in both cohorts.

Abstract

Cervical insufficiency or sonographic short cervix is a major cause of preterm birth (PTB). The efficacy of two-stitch versus one-stitch cerclage remains controversial, with limited evidence from randomized controlled trial (RCT), especially stratified by indication.

We conducted a single-centre, stratified, exploratory RCT at Fujian Maternal and Child Health Hospital, Fuzhou, China. Women with singleton pregnancies were enrolled into two parallel cohorts: a therapeutic cohort (ultrasound-indicated; cervical length ≤ 25 mm at 16–28 weeks) and an emergency cohort (physical examination-indicated; painless cervical dilatation with or without membrane exposure at 16–28 weeks). Within each cohort, participants were randomly assigned (1:1) to receive McDonald cerclage with either two-stitch or one-stitch. The primary outcome was spontaneous PTB < 34 weeks. RR with 95% CI was calculated as the primary measure of effect size between groups.

Between June 2022 and December 2024, 100 women were enrolled and stratified (therapeutic, n = 50; emergency, n = 50). In the intention-to-treat (ITT) analysis, there was no significant difference in the primary outcome of spontaneous PTB < 34 weeks between the two-stitch and one-stitch groups in the therapeutic cohort (16.0% vs 0.0%; RR not calculable; p = 0.110) or the emergency cohort (40.0% vs 48.0%; RR 0.83, 95% CI 0.44–1.57; p = 0.569). However, an exploratory analysis of the emergency cohort revealed that the two-stitch technique was associated with a reduced incidence of PTB < 28 weeks (12.0% vs 40.0%; RR 0.30, 95% CI 0.09–0.96; p = 0.024). Neonatal survival rates did not differ significantly in either cohort.

In the therapeutic setting, the two-stitch technique was not superior to the one-stitch approach. For emergency cerclage, while the primary outcome was not significantly reduced, a secondary analysis showed an association between the two-stitch technique and a reduced incidence of extreme PTB < 28 weeks. This hypothesis-generating finding suggests a potential benefit in preventing extreme PTB < 28 weeks and must be validated in larger, definitive trials.

The Chinese Clinical Trial Registry (ChiCTR), Identification Number ChiCTR2200058540. https://www.chictr.org.cn/bin/project/edit?pid=159942.

The online version contains supplementary material available at 10.1186/s12884-026-08809-8.

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