Some Data Suggest Planned C-Section May Be Best for Vertex/Nonvertex Twins


SAN FRANCISCO — Recent data may make trials of labor to deliver twins in vertex/nonvertex positions a thing of the past, Yasser Y. El-Sayed, M.D., predicted.

A large retrospective cohort study found significantly greater safety in planned cesarean deliveries, compared with vaginal delivery of both twins or vaginal delivery of the first (vertex) twin and an emergency C-section after a failed attempt at vaginal delivery of the second (nonvertex) twin (Am. J. Obstet. Gynecol. 2005;192:840–7).

“Breech extraction of the second twin may very well go the way of the singleton breech” delivery, said Dr. El-Sayed of Stanford (Calif.) University.

Breech delivery of singletons generally has been shunned since the 2000 Term Breech Trial found greater morbidity from vaginal breech deliveries of singletons, compared with planned C-sections (Lancet 2000;356:1375–83).

The more recent study looked at all U.S. twin births in 1995–1997 and found 15,185 twin vertex/nonvertex pairs delivered when they were at or greater than 24 weeks' gestation and weighed at least 500 g. In 37.7% of cases, both twins were delivered by planned C-section, and in 46.8%, both twins were delivered vaginally. In 15.5%, the first twin was delivered vaginally and a trial of labor failed for the nonvertex twin, who then was delivered by emergency C-section.

Compared with the planned C-section group, babies in the vaginal delivery-only group had significantly higher rates of all-cause neonatal death, death not related to congenital anomalies, asphyxia-related death, newborn infant injury, low Apgar scores, ventilation use, and seizures.

The emergency C-section group had significantly higher rates of asphyxia-related death, newborn infant injury, low Apgar scores, and ventilation use, compared with the planned C-section group.

Many of these differences remained in subgroup analyses of infants weighing less than or more than 1,500 g. That finding contradicts the results of less well-designed retrospective studies suggesting that breech delivery of a nonvertex twin was safe for babies weighing at least 1,500 g, Dr. El-Sayed noted.

Authors of the twin study said their results were consistent with those of the singleton Term Breech Trial and concluded that planned C-section delivery causes the least morbidity to nonvertex second twins or to singletons.

In the twin study, emergency C-sections were needed for almost 25% of nonvertex twins who underwent an attempted vaginal delivery.

“The authors of the study suggest that perhaps this alone should lead to routine cesarean section for vertex/nonvertex twins,” Dr. El-Sayed said.

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