News

A woman who has a cesarean section faces a small but not insignificant risk of harming her baby and herself if the next delivery is a natural one, according to a new study.

The research, published in today's edition of the New England Journal of Medicine, is sure to add fuel to the long-standing debate about when it is necessary and appropriate to deliver a baby by cesarean.

But Vyta Senikas, associate executive vice-president of the Society of Obstetricians and Gynecologists of Canada, said the real value of the study is to provide women with hard facts on which to base their decisions.

"The real issue here is informed consent. The more evidence we have, the better it is," Dr. Senikas said. "Doctors should not force women to choose one way or another -- vaginal or cesarean birth -- but they should provide the best factual information possible on the risks."

Mark Landon, a professor of obstetrics and gynecology at Ohio State University in Columbus, Ohio, said the baby is affected in about one in every 2,000 births if the mother chooses a natural vaginal birth after cesarean (VBAC).

"The absolute risks are low," he said, "but greater than an elective repeated cesarean without labour."

The study involved 45,988 women in the United States who had had a previous cesarean section (a surgical procedure performed to deliver a baby, usually when the mother or child is experiencing a complication that puts one or both of them at risk). Of the total, 39 per cent opted for a natural delivery, and 34 per cent for an elective cesarean. The rest either had a medical reason for a cesarean or arrived at the hospital already in labour, so they were excluded from the findings.

Researchers found that among women attempting a VBAC, seven per 1,000 suffered uterine rupture, a complication that is dangerous for both baby and mother. There were no uterine ruptures in the cesarean group.

Endometritis -- an inflammation of the uterus -- developed in 2.9 per cent of the women who chose natural birth, compared to 1.8 per cent of those who opted for a cesarean. In the VBAC group, 1.7 per cent required a blood transfusion, compared to 1 per cent in the cesarean group.

Michael Greene, director of maternal-fetal medicine at Massachusetts General Hospital in Boston, who wrote an editorial accompanying the study, said every woman and doctor will interpret those statistics differently. "Risk is in the eye of the beholder," he said.

Dr. Senikas, who is also a high-risk obstetrician at Royal Victoria Hospital in Montreal, said that is true, but added that "when the patient becomes the statistic, it's always a grave event."

She said the biggest issue is that "it's impossible to predict who will suffer complications" in the VBAC group. As a result, many of these women opt for a cesarean, particularly if they know that they, rather than the baby, will have the greatest risk of complications as a result.

"If a woman has to choose between possible harm to herself and possible harm to the fetus -- no matter how small or large the risk -- she almost always chooses herself," Dr. Senikas said.

According to data released this year by the Canadian Institute for Health Information, three in four births in Canada involve some form of surgical intervention: cesarean sections, epidurals, forceps, vacuum extraction and episiotomies are all commonplace. There are about 330,000 births in Canada annually. One in five babies are delivered by cesarean section, but rates vary widely by region.