BMJ Open (May 2024)

Study protocol for two randomised controlled trials evaluating the effects of Cerclage in the reduction of extreme preterm birth and perinatal mortality in twin pregnancies with a short cervix or dilatation: the TWIN Cerclage studies

  • Ben W Mol,
  • Martijn A Oudijk,
  • Enrico Lopriore,
  • Judith O E H van Laar,
  • Yves Jacquemyn,
  • Eva Pajkrt,
  • Marjon A de Boer,
  • Judith Bosmans,
  • Isabelle Dehaene,
  • Sam Schoenmakers,
  • Jelmer R Prins,
  • Ruben Duijnhoven,
  • Jan B Derks,
  • Wilfried Gyselaers,
  • Caroline Van Holsbeke,
  • Salwan Al-Nasiry,
  • Joris van Drongelen,
  • Lissa van Gils,
  • Margo Lutke Holzik,
  • Marieke H Knol,
  • Liesbeth Lewi,
  • Hannes van der Merwe,
  • Sylvia A Obermann-Borst,
  • Mayella Holthuis

DOI
https://doi.org/10.1136/bmjopen-2023-081561
Journal volume & issue
Vol. 14, no. 5

Abstract

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Introduction Twin pregnancies have a high risk of extreme preterm birth (PTB) at less than 28 weeks of gestation, which is associated with increased risk of neonatal morbidity and mortality. Currently there is a lack of effective treatments for women with a twin pregnancy and a short cervix or cervical dilatation. A possible effective surgical method to reduce extreme PTB in twin pregnancies with an asymptomatic short cervix or dilatation at midpregnancy is the placement of a vaginal cerclage.Methods and analysis We designed two multicentre randomised trials involving eight hospitals in the Netherlands (sites in other countries may be added at a later date). Women older than 16 years with a twin pregnancy at <24 weeks of gestation and an asymptomatic short cervix of ≤25 mm or cervical dilatation will be randomly allocated (1:1) to both trials on vaginal cerclage and standard treatment according to the current Dutch Society of Obstetrics and Gynaecology guideline (no cerclage). Permuted blocks sized 2 and 4 will be used to minimise the risk of disbalance. The primary outcome measure is PTB of <28 weeks. Analyses will be by intention to treat. The first trial is to demonstrate a risk reduction from 25% to 10% in the short cervix group, for which 194 patients need to be recruited. The second trial is to demonstrate a risk reduction from 80% to 35% in the dilatation group and will recruit 44 women. A cost-effectiveness analysis will be performed from a societal perspective.Ethics and dissemination This study has been approved by the Research Ethics Committees in the Netherlands on 3/30/2023. Participants will be required to sign an informed consent form. The results will be presented at conferences and published in a peer-reviewed journal. Participants will be informed about the results.Trial registration number ClinicalTrials.gov, NCT05968794.