Cervical length at 23 weeks in triplets: prediction of spontaneous pretermdelivery

Objectives To establish the distribution of cervical length at 23 weeks of gestation in triplet pregnancies and to examine the relation to preterm del ivery before 33 weeks. Methods Cervical length was measured by transvaginal sonography at 23 (rang e 22-24) weeks of gestation in 43 triplet pregnancies. The distribution of cervical length was determined and the relationship between cervical length and the rate of spontaneous preterm delivery before 33 weeks was calculate d. Results The cervical length distribution was skewed to the left with a medi an of 34 mm. The rate of spontaneous labor and delivery before 33 weeks inc reased exponentially with decreasing cervical length at 23 weeks from 8% at 36-48 mm, to 11% at 26-35 mm, 33% at 16-25 mm and 67% at 15mm or less. Cer vical length was less than or equal to 30 mm, less than or equal to 25 mm a nd less than or equal to 15 mm in 37%, 16% and 8% of cases, respectively: a nd the corresponding sensitivities in the prediction of spontaneous deliver y before 33 weeks were 67%, 50% and 33%. Conclusions In triplet pregnancies, measurement of cervical length provides a useful prediction of risk: for spontaneous early preterm delivery.