Success Rates Similar for Preterm, Term VBAC


MIAMI BEACH — A trial of labor should be considered an option for women with a history of prior cesarean delivery when preterm delivery is anticipated, Dr. Celeste P. Durnwald said at the annual meeting of the Society for Maternal-Fetal Medicine.

“There is little information reported to date on the efficacy of a [vaginal birth after cesarean] attempt in women undergoing preterm delivery,” said Dr. Durnwald, who presented a study on behalf of the National Institute of Child Health and Human Development maternal-fetal medicine units network.

One other research team has addressed the impact of preterm vaginal birth after cesarean (VBAC), said Dr. Durnwald of Ohio State University, Columbus. Investigators in that study reviewed medical records for 20,156 women with a singleton fetus and history of one cesarean delivery, including 12,463 (62%) who attempted a VBAC. They compared women who delivered preterm, at a mean of 34 weeks, with a group who delivered full term, at a mean of 39 weeks. VBAC was successful for 82% of the preterm group and 74% of the term group, a statistically significant difference. The study, however, was retrospective (Obstet. Gynecol. 2005;105:519–24).

Dr. Durnwald and her associates assessed 3,119 women with a preterm pregnancy. Of these, 2,338, or 75%, attempted a trial of labor. The researchers compared the success of VBAC and the rates of uterine rupture and maternal morbidities in these women with those in a control group of 15,331 women who attempted a trial of labor at term. The groups were similar, except women in the preterm group were more likely to be African American, government insured, and smokers.

VBAC was successful for 72.8% of the preterm group and 73.2% of the term group, Dr. Durnwald said. Rates of uterine rupture (0.34% vs. 0.74%, respectively) and dehiscence (0.26% vs. 0.73%) were lower in the preterm group.

Significantly more women in the preterm group had coagulopathy and/or a need for transfusion, according to a multivariate analysis.

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