"That's definitely a trend and we (do) see that as well in the United States," said Dr. Henry Lee at Benioff Children's Hospital at the University of California, San Francisco.

Most babies are born head first, but in three to four percent of pregnancies, babies close to delivery are in a feet-first orientation that can make the trip through the birth canal more difficult and dangerous for both baby and mother.

In 2000, a landmark study called the Term Breech Trial found that breech babies born vaginally were three times more likely to suffer serious harm or death compared to babies born via cesarean. C-sections, the study concluded, were the safer way to deliver breech babies.

To see whether that study has influenced how breech deliveries are handled in Ireland, Dr. Mark Hehir, of the National Maternity Hospital and the Rotunda Hospital in Dublin, and his colleagues collected information on all deliveries at three major medical centers in the capital over a 16-year period.

About 5,600 breech babies were born in the eight years before the Term Breech Trial was published and roughly 6,200 afterward.

Among first-time moms delivering breech babies, the rate of vaginal births was 15 percent before that study and dropped to seven percent in the years following.

Similarly, mothers who already had kids delivered a breech baby vaginally 33 percent of the time before 2000 and 15 percent of the time after.

Though it appears that women and their clinicians are following the recommendations from the 2000 study, Hehir points out that vaginal deliveries of breech babies were already declining before the Term Breech Trial was published.

Between 1993 and 1997, about 30 percent of all breech babies were delivered vaginally, compared to 18 percent between 1997 and 2000.

Hehir said that a general increase in the popularity of cesarean delivery has contributed to declining vaginal deliveries for breech babies. But the Term Breech Trial also likely played a role.

One concern raised by the fall-off in vaginal breech births, he noted, is that doctors are not getting as much experience with them.

In its report in the American Journal of Obstetrics and Gynecology, Hehir's group writes, "Our findings would suggest that vaginal breech delivery in the future may be limited by the decreasing numbers of clinicians adequately skilled to conduct these deliveries safely."

Lee, who was not involved in the Irish study, said that while C-sections are becoming the mainstay for breech births, not everybody agrees that it's the optimal mode of delivery every time.

"I think probably we can say that in many situations cesarean section probably is the safer way to deliver breech babies," Lee told Reuters Health. "Whether some breech babies might be delivered vaginally safely, that's a question that's open to study."

Hehir's study did not determine whether one delivery method was safer for the mothers or babies than the other, but the paper does note that "there was no significant decline in prenatal mortality rates" over the 16-year study, "despite a significant decrease in vaginal breech deliveries" during the same period.

Hehir said that some studies have shown that for certain women, vaginal delivery can be just as safe an option as cesarean.

"Without a doubt the vast majority of babies in breech presentation will be delivered by cesarean section," Hehir said. "But I think vaginal delivery can be achieved successfully with a little bit of careful selection" of mothers.

SOURCE: bit.ly/HyfvWs American Journal of Obstetrics and Gynecology, online March 30, 2012.

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