A major complication of twins is spontaneous preterm delivery. Management of preterm birth risk in twins is unclear; evidence suggests cerclage does not improve outcome, and may even increase risk but women with prior history of ptb may benefit. The benefit of cerclage in the management of twins with prior history is therefore uncertain.

We compared cerclage use and outcome in 124 sets of twins with (n = 36) and without (n = 88) a prior history of spontaneous ptb and/or midtrimester loss managed in a specialist preterm birth clinic. All women had longitudinal cervical scanning from referral or 16 weeks. Cerclage was inserted <24/40 if membranes were visible or if fFN was positive and cervical length <15 mm.

Significantly more women in the prior history group required cerclage: 7/36 [19%] vs 4/88 [5%], chisquare 7.01, p < 0.01. Delivery rates <30 weeks were similar in both groups: 5/88 [6%] vs 3/36 [8%], chisquare 0.29, NS. There was a non significant trend towards higher preterm birth rates <34/40 in the prior history group: 11/88 [13%] vs 8/36 [22%], chisquare 1.86, NS. All women (n = 7) who received emergency cerclage for exposed membranes had live twins at birth.

Ultrasound indicated cerclage is more common in twins with a prior history of ptb. When managed as such preterm birth <30/40 no more common than women without a history. The role of cerclage in twins requires further research particularly in relation to the effect of a prior history of ptb where cerclage maybe beneficial. Emergency cerclage is often successful in twins.