Role of transvaginal sonographic cervical length in predicting spontaneous preterm delivery in triplet pregnancies with therapeutic cerclage.

OBJECTIVE

To assess the role of transvaginal sonographic cervical length in predicting spontaneous preterm delivery at < 32 weeks in patients with both triplet pregnancy and therapeutic cerclage.

STUDY DESIGN

The maternal records of all triplet pregnancies with therapeutic cerclage and sonographic cervical length before and after cerclage were reviewed (n = 17). Each of these triplet gestations was matched with 2 triplet pregnancies without cerclage based on cervical length after cerclage (+/- 0.5 cm) and gestational age (+/- 3 weeks). Statistical analysis included Fisher's exact test or chi 2 analysis, one-way analysis of variance, logistic regression analysis and receiver operating characteristic curve analysis.

RESULTS

Cerclage was placed at a gestational age of 19.0 +/- 3.1 weeks (mean +/- SD) and increased cervical length from 2.0 +/- 0.7 cm to 3.1 +/- 1.4 cm (P < .05). The rate of spontaneous preterm delivery at < 32 weeks was higher among cases than controls (7/17 vs. 4/27, P = .08). Logistic regression analysis demonstrated that only postcerclage cervical length was predictive of spontaneous preterm delivery at < 32 weeks, with a cervical length of 3.3 cm the optimal predictor.

CONCLUSION

In women with triplets and therapeutic cerclage, the only significant predictor of spontaneous preterm delivery at < 32 weeks is cervical length after cerclage placement.