Cerclage benefits subset of high-risk women.(OBSTETRICS)(Clinical report)

SAN DIEGO -- Women with prior early spontaneous preterm birth and a midtrimester sonographic cervical length of less than 25 mm may benefit from cerclage, but the benefit is most pronounced when the cervical length is less than 15 mm, results from a large, multicenter, randomized study showed.

"Although clinicians have recommended cerclage for shortened cervical lengths, previous randomized trials have not supported this practice," Dr. John Owen said at the annual meeting of the Society for Maternal-Fetal Medicine.

A recent meta-analysis of four randomized trials of cerclage for shortened cervical length uncovered a relationship between pregnancy history and cerclage effectiveness. Cerclage was helpful only in singletons--it was harmful in multiples--but it was especially helpful in women who'd had a prior preterm birth (Obstet. Gynecol. 2005; 106:181-9).

"Our hypothesis was that in women with a prior early spontaneous preterm birth [gestational age less than 34 weeks] and cervical length less than 25 mm, cerclage would reduce the rate of preterm birth before 35 weeks' gestation," said Dr. Owen of the department of obstetrics and gynecology at the University of Alabama at Birmingham.

To test the hypothesis, he and his colleagues at 15 centers in the United States, known as the Vaginal Ultrasound Trial Consortium, studied 1,014 women with a prior spontaneous birth at less than 34 weeks and a current singleton pregnancy who underwent serial ultrasound evaluation in the period ...