MAVRIC: A Multicentre Randomised Controlled Trial of Transabdominal versus Transvaginal Cervical Cerclage

Abstract

Background: Vaginal cerclage (a suture around the cervix) is commonly placed in women with recurrent pregnancy loss. These women may experience late miscarriage or extreme preterm delivery, despite being managed with cerclage. Transabdominal cerclage (TAC) has been advocated following failed cerclage, although its efficacy is unproven by randomised controlled trial (RCT). Methods: A multicentre RCT to compare TAC or high vaginal cerclage (HVC) to low vaginal cerclage (LVC), as a preventative strategy for spontaneous preterm birth (sPTB) in women with history of a failed cerclage was undertaken. Women were randomly assigned (1:1:1) to receive TAC, HVC or LVC, either prior to conception or before 14 weeks' gestation. Primary outcome was delivery before 32 completed weeks of pregnancy. Findings: 111/139 women recruited who conceived were analysed: 39 to TAC, 39 to HVC and 33 to LVC. Rates of sPTB<32 weeks were significantly lower in women who received a TAC compared to LVC [8% (3/39) v 38% (15/39), RR 0.23 (95% CI 0.07 to 0.76), p=0⋅0078]. Number needed to treat (NNT) to prevent one sPTB was 3⋅9 (95% CI 2⋅2 to 13⋅3). There was no difference in sPTB rates between HVC and LVC [38% (15/39) vs 33% (11/33), RR 1⋅15 (95% CI 0⋅62 to 2⋅16), p=0⋅81]. No neonatal deaths occurred. Women with TAC had fewer fetal losses compared to LVC [3% (1/39) vs 21% (7/33), RR 0⋅12 (95% CI 0⋅016 to 0⋅93), p=0⋅02]. NNT to prevent one fetal loss was 5⋅3 (95% CI 2⋅9 to 26). Interpretation: TAC is the treatment of choice for women with failed vaginal cerclage. It is superior to LVC in reducing risk of early PTB and fetal loss in women with previous failed vaginal cerclage. HVC does not confer this benefit. NNT are sufficiently low to justify transabdominal surgery and caesarean delivery required in this select cohort. Trial Registration Number: The trial was registered with the WHO International Clinical Trials Registry Platform (ISRCTN33404560) Funding Statement: J P Moulton Charitable Foundation (Registered Charity No. 1109891). PTS is partly funded by Tommy's (Registered charity no. 1060508) and by CLAHRC South London (NIHR). Declaration of Interests: The authors state: None to declare. Ethics Approval Statement: NHS Research Ethical Committee approval was obtained (REC 07/H1102/113).