Emergency cerclage in twin pregnancies at imminent risk of preterm birth: an open-label randomised controlled trial (ENCIRCLE)

Twin pregnancies are at an increased risk of early delivery. One of the reasons for this may be due to a weakened neck of the womb (cervix).

There are two main ways to manage a weakened cervix in pregnancy. One option is to do nothing (conservative approach). The other is to strengthen the cervix with a stitch (cerclage) to provide extra support. There is no good quality convincing evidence to suggest which of these has better outcomes for mum and babies in twin pregnancies.

This trial aims to determine whether securing the weakened cervix with a cerclage will help to prolong the pregnancy and prevent early delivery. Babies who are born early can experience multiple complications including lung, brain and learning difficulties. Therefore, the study will also aim to determine whether prolonging the pregnancy by inserting the cerclage reduces the number of babies affected by these problems.

In order to ensure this is a fair study, it is being carried out as a randomised controlled trial. There are two major groups in the trial: (1) women pregnant with twins, who present with a weakened cervix and no signs of infection between 14 and 26 weeks of pregnancy. This will be diagnosed by an internal examination or ultrasound scan, and (2) women pregnant with identical twins complicated by twin-to-twin transfusion syndrome (TTTS) treated by Laser surgery between 16 and 26 weeks in whom a short cervix (<15mm) is identified.

Cervical length is a strong predictor of preterm delivery in these pregnancies. Participants will be allocated randomly into the intervention (cerclage) or control (conservative) group. Women in both groups will be followed up in the same manner until they deliver, and the pregnancy outcomes will be compared between the 2 groups to determine which management option is best.

You can follow the latest updates on the study here: https://twitter.com/ENCIRCLEtrial

This research is has been was funded by the Twins Trust and BMFMS research bursaries Twins Trust and carried out by St George's Hospital, London. It has been match funded by BMFMS.