Cerclage outcome by the type of suture material (COTS): study protocol for a pilot and feasibility randomised controlled trial

BACKGROUND Cervical incompetence is one of the causes of preterm birth and mid-trimester pregnancy loss. Cervical cerclage is a surgical procedure to treat cervical incompetence. Cervical cerclage reduces the incidence of preterm birth in women at risk of recurrent preterm birth, without a statistically significant reduction in perinatal mortality or neonatal morbidity. Multifilament/braided sutures such as Mersilene tape have been traditionally used for cervical cerclage. Braided sutures, particularly mesh-like non-absorbable sutures, have been associated with an increased risk of infection and, hence, some obstetricians prefer to use monofilament/non-braided sutures. However, these claims are not substantiated by any scientific or clinical evidence.We propose a pilot/feasibility study which will provide the necessary information for planning a definitive trial investigating the clinical effectiveness of monofilament non-braided suture materials in reducing pregnancy loss rate following cervical cerclage compared to the traditional multifilament braided sutures. METHODS/DESIGN Women eligible for elective or ultrasound-indicated cerclage at 12 to 21 + 6 weeks of gestation will be randomised to having the procedure using either a monofilament non-braided suture (Ethilon) or a Multifilament braided suture (Mersilene tape) inserted using a McDonald technique. Consent for participation in the Cerclage outcome by the type of suture (COTS) study will be obtained from each eligible participant. CLINICAL TRIALS REGISTRATION COTS is registered with the International Standard Research for Clinical Trials (ISRCTN17866773). Registered on 27 March 2013.