With her due date approaching and her unborn son pointed feet first, Fiona Simmonds tried every technique she knew of—acupuncture, raising her pelvis above her head and playing music near her belly—to encourage the baby to flip around and allow him be delivered normally. But in the end, the baby remained breech and she needed a caesarean section.

Today, about a third of U.S. births are done by caesarean section, up from 21% in 1998, one of the highest of any developed country, the National Center for Health Statistics reported in March. Public health officials are concerned about the rising rate because c-sections hold more health risks for the mother—including possible infection and blood loss—and are more expensive than a vaginal birth.

Medical experts say many c-sections—which involve delivering a baby through a surgical incision—are performed unnecessarily. But for a growing number of women, a c-section is the safer option for delivering a baby, and in some emergency cases, it might be the only choice. Medical experts say they're now seeing more medically-necessary c-sections as women have children later in life and obesity rates rise.

"We're seeing more obese women and that leads to more" caesareans because they are more likely to have other medical conditions that can lead to complications during childbirth, such as diabetes and high blood pressure, says Jacques Moritz, director of gynecology at St. Luke's-Roosevelt Hospital Center in New York.

Moms with diabetes tend to have larger babies that can get stuck in the birth canal and obesity can make it more difficult to monitor the baby during delivery. Older moms are more likely to experience complications during pregnancy such as gestational diabetes and preeclampsia (a condition characterized by high-blood pressure during pregnancy), which can boost the risk of a c-section. And the increased use of fertility treatments including in-vitro fertilization, which can result in multiple births, also can make a c-section necessary, Dr. Moritz says.

When a baby weighs more than 10 pounds, a c-section is often the safer option. Dr. Moritz also chooses a c-section when the mother has been in labor for a long period and not able to deliver. A long labor could signal that the baby is having trouble fitting through the mom's pelvis. A caesarean also is necessary for twins whose heads are not pointed down and anytime there are triplets, he says. And c-sections are often ordered when a baby's heart rate goes down during labor.

The number of c-sections performed in the U.S. each year for medical reasons isn't counted. But the World Health Organization has said that when c-sections rates go above 15% of total births, that usually indicates too many are being done.

"There is no question we're doing a lot more c-sections than necessary," says Bruce Meyer, executive vice president for health system affairs and professor in the department of obstetrics and gynecology at UT Southwestern Medical Center in Dallas.

He says several factors including doctors' fear of litigation, a growing demand among patients for elective caesareans that aren't medically necessary and more induced labors have contributed to the growing rates of c-sections. "People will come into my office and say, 'you're not going to let me go past my due date,"' Dr. Meyer says. He says induced pregnancies are more likely to end up with a c-section than if the woman goes into labor on her own.

Dr. Meyer says most women won't try a vaginal birth after a c-section, known as a VBAC. Many are worried about the risk of a uterus rupturing, which happens about 1% of the time. But VBAC's are usually successful: About 74% of women who have had a c-section and try to deliver vaginally are able to do so, according to a National Institutes of Health panel. Dr. Meyer says he will recommend a VBAC under certain circumstances, including when a woman has had only one previous caesarean using certain types of incisions.

Dr. Meyer says that when attempting a VBAC, a woman should be in a hospital with round-the-clock anesthesiologists and obstetricians who can perform an emergency c-section within 20 minutes if the need arises.

Some of the highest rates of c-sections are in states like New Jersey, Florida, Louisiana, Mississippi and West Virginia with more than 35%, while the lowest rates are found in Alaska, Idaho, New Mexico and Utah with rates less than 25%.

The rise in caesarean sections hasn't resulted in fewer delivery complications or healthier moms and babies, says George A. Macones, chairman of obstetrics and gynecology at Washington University in St. Louis and a spokesman for the American College of Obstetricians and Gynecologists.

"Seeing it the rate of c-sections continue to increase without seeing women or babies do better is not good," Dr. Macones says. "It's got to be for good solid medical reasons, not because of pressure from the patients or out of fear of liability."

Women who deliver a baby by caesarean section face a number of medical risks, including the possibility of infection, blood loss, pulmonary embolism and death. The risks are magnified after a first child is delivered by c-section: In subsequent pregnancies, there's an increased likelihood that the uterus could rupture. Second and third c-sections also have higher risks of excessive bleeding that could necessitate a hysterectomy.

"It's the long term complications of multiple caesareans" that people need to be most aware of, Dr. Meyer says.

Vaginal deliveries, of course, carry their own risks, the most common of which are pain and trauma to the pelvic floor, which can sometimes result in incontinence. But they are generally safer than c-sections, Dr. Meyer says. And there are also health benefits for babies: Passing through the birth canal helps prepare the lungs for breathing air.

But doctors say that a c-section is indicated if a normal delivery would be risky for baby or mom. When Mrs. Simmonds baby failed to move out of the breech position, she scheduled a caesarean.

"It's always something you think about because birth is so unpredictable," says the 32-year-old from New York whose son Charlie was born last month. "There was no alternative."

Source : online.wsj.com