Introduction

Preterm birth (PTB) is a serious global health issue, accounting for a large proportion of neonatal mortality and long-term health problems. The risk is even greater in twin pregnancies, where preterm birth rates are significantly higher than in singletons [1,2]. Various interventions have been investigated to prevent preterm birth, such as administration of progesterone, placement of cervical cerclage, and an Arabin pessary [3]. Nevertheless, the efficacy of these measures in multiple gestations is still unclear.

Twin pregnancies are classified by chorionicity and amnionicity, with dichorionic diamniotic (DCDA) twins being the most common type resulting from the fertilisation of two separate eggs (dizygotic twins). DCDA twins have separate placentas and amniotic sacs, which generally lowers some risks compared to monochorionic twins, though the risk of preterm birth remains high. Cervical incompetence, also known as cervical insufficiency, is a condition in which the cervix painlessly dilates and shortens during the second trimester, increasing the risk of mid-trimester pregnancy loss or preterm delivery [1]. It may be diagnosed based on clinical history or ultrasound findings of painless cervical dilation or shortening, especially in women with a history of recurrent pregnancy loss or preterm birth.

Cervical cerclage is a surgical procedure performed to reinforce the cervix with a suture, typically between 12 and 24 weeks of gestation [2]. The most common technique is the McDonald procedure, which involves placing a purse-string suture around the cervix via the vagina. Cerclage may be indicated in women with a history of cervical insufficiency, findings of cervical shortening, or painless dilation on examination. Notably, the role of cerclage in twins is controversial, with current research indicating that its benefit may be confined to certain high-risk cases, particularly those with evidence of cervical shortening or early dilation [4,5].

This case highlights the use of emergency McDonald cerclage in a DCDA twin pregnancy complicated by advanced cervical shortening and early cervical dilatation, contributing to the growing body of evidence supporting carefully selected use of cerclage in high-risk twin gestations.

The abstract was previously presented as an e-poster at the RCOG World Congress, held in London from 23-25 June, 2025.