Prediction of spontaneous preterm birth in asymptomatic twin pregnancies using the change in cervical length over time.

Abstract

We sought to evaluate the change in cervical length (CL) as a predictor of preterm birth in asymptomatic twin pregnancies. We studied a historical cohort of 121 twin pregnancies with CL testing between 18-24 weeks who had a follow-up CL 2-6 weeks after the initial CL. A total of 19 patients had their CL decrease by > or = 20% (shortened CL group) and 102 patients' CL decreased by less, or not at all (stable CL group). The shortened CL group had a significantly higher rate of spontaneous preterm birth <28 weeks, <30 weeks, <32 weeks, and <34 weeks. This remained true even when excluding patients with a short CL (< or = 25 mm) on the repeated CL. In twin pregnancies, a CL that decreases by 20% over 2 measurements is a significant predictor of very preterm birth, even in the setting of a normal CL. Serial CL measurements should be considered in twin pregnancies, starting <24 weeks.