Five years ago, Jill Arnold got some unwanted news at her obstetrician's office. At 37 weeks pregnant, Arnold was told her baby was too big for her body to deliver naturally. Flipping open a calendar, the obstetrician asked when Arnold would like to schedule a cesarean section.

Unconvinced she needed the surgery — the doctor "couldn't provide any statistics or data" her baby was too large — Arnold delivered her 10-pound, 3-ounce (4.6 kilogram) baby the old-fashioned way. Since then, the now 36-year old who lives in San Diego, delivered another baby weighing 11 pounds, and now pens a blog called The Unnecesarean.

Women like Arnold, however, are becoming increasingly rare. Between 1996 and 2007, the number of C-sections performed in U.S. hospitals rose by more than 50 percent to an all-time high: Almost one in three pregnant women, regardless of race or ethnicity, now delivers via a cesarean section, according to the Centers for Disease Control and Prevention.

"The most concerning problem is the high rate in first-time mothers," said Dr. Jun Zhang, a medical researcher at the National Institutes of Health and co-author of a new report on cesarean delivery practices.

In his study, published in the American Journal of Obstetrics & Gynecology last month, Zhang looked at medical records of 228,668 women who had delivered babies in 19 hospitals across the country, to determine the factors involved in cesarean deliveries.

The study underscored a shift — one that has been in the making since the mid-twentieth century — in how hospitals approach the birth process. The shift is toward a more streamlined labor and delivery, and profoundly affects mothers-to-be.

In the case of rising C-sections, Zhang wrote in the report, this shift is not likely to reverse any time soon.

A need for clearer guidelines

In 2009, 26-year old Ann Carter (whose name has been changed) of Gonzales, La., had labored for 14 hours. With her cervix dilated to only 6 centimeters (a woman is ready to give birth when the dilation reaches 10 centimeters), her doctor told her it was time for a C-section.

"I was devastated and scared," Carter said, "I knew it was a possibility but I was hoping it wouldn't happen."

During the surgery, the doctor discovered the umbilical cord had wrapped around the baby's neck, which explained why Carter's labor had stalled. The C-section saved the baby boy's life.

"Most times the decision to perform a C-section is based on the physician's judgment," Zhang said, "but there are great variations in decision-making among physicians."

Although there are certainly instances, such as Carter's, in which a C-section is necessary and lifesaving, Zhang said, there are "few clear-cut indications" of when to do one.

This is especially true of risks that are newcomers to the public health scene, such as moms of older age and rising levels of obesity, he said. Seemingly by default, the result has been more C-sections.

For example, the American Congress of Obstetricians and Gynecologists (ACOG) lists "failure to progress" during labor, as an indication that cesarean delivery is needed. A woman's cervix should dilate by a certain amount each hour. When things slow down, there is an element of judgment involved where a physician determines whether to continue to wait, induce or perform a C-section. According to ACOG, it can take hours to determine whether or not labor is progressing.

In Zhang's study, however, he found that many patients weren’t given a sufficiently long time period to allow their labor to progress. In other words, doctors were calling it quits on waiting and opting for a C-section too soon — often before the patient's cervix was dilated to 6 centimeters.

This was especially true in cases of induced labor, during which a woman is given the hormone oxytocin (also called by its brand name, Pitocin) to initiate labor: Almost half of the C-sections in these women occurred before they were 6 centimeters dilated, Zhang found.

Still, it is not clear whether inducing labor raises the risk of C-section, or whether other factors are involved that contribute to why women were induced in the first place, Zhang told MyHealthNewsDaily.

"It's a good question, and one that we're currently working on," Zhang said.

Practicing defensive medicine

Another factor contributing to the record-high cesarean rates is a drastic decline in vaginal births after cesarean (VBAC). Zhang found that 70 percent of women in his study who had previously undergone a cesarean delivery had C-sections with their subsequent pregnancies, without attempting vaginal delivery.

One reason for this is a fear of lawsuits. If a physician doesn't perform a C-section, and something goes wrong with a patient who previously had a C-section, the law often does not protect the physician, said Dr. Daniel Roshan, an obstetrician and gynecologist (ob-gyn)  at New York University Langone Medical Center.

According to the Physician Insurers Association of America, which provides protection to more than 60 percent of private practice physicians in the country, the number of malpractice claims involving obstetric and gynecologic surgery are the second highest of all medical specialties. In 2009, the claims totaled over $133 million.

Fears of legal action also explain why at least 30 percent of all U.S. hospitals have official bans prohibiting VBACs, according to the International Cesarean Awareness Network (ICAN). And the number of hospitals with de facto bans likely brings the total much higher.

"Doctors are practicing legal medicine, not real medicine," Roshan said.

The risks associated with a vaginal birth following a C-section have been somewhat exaggerated, however, Zhang said.

"Women and physicians may be concerned about uterine rupture, but the risk is less than 1 percent," Zhang said. "More than half of all women can have a successful VBAC."

To help reduce rising cesarean rates, the American Congress of Obstetricians and Gynecologists announced less restrictive guidelines in July, stating that vaginal birth "has fewer complications than a repeat cesarean….restrictive VBAC policies should not be used to force women to undergo a repeat cesarean delivery against her will."

"We're hopeful that this statement will push hospitals to reverse their bans, but we haven't seen significant change yet," said Krista Cornish Scott, the education director of ICAN, who herself had two complication-free VBACs.

Although controversial, some medical experts have suggested the rapid rise of C-sections in the last decade is also due in small part to mothers-to-be requesting them, not doctors. Still, data on "patient choice cesareans" is lacking, as statistics used as support of their frequency are often based on ambiguous procedural codes used on hospital discharge records.

In any case, women who opt for a C-section may not be getting adequate information about risks, and may fear they have no other option.

"Women need to know that they have choices," said Dr. Lizellen La Follette, an ob-gyn in Greenbrae, Calif., adding "and that a C-section is not always a safer birth method."

Re-thinking the birthing process

In the book "Birthing a Better Way: 12 Secrets for Natural Childbirth" (University of North Texas Press, 2010), co-author and ob-gyn Dr. Margaret Christensen wrote in the preface, "I was only taught that birth is a disaster until proven otherwise, best medicated, medicalized, managed and controlled."

This has been the prevailing view since the 1950s, and the result has been an increasingly streamlined process of labor and delivery, in which C-sections are often the "quicker and easier method" NYU obstetrician Roshan said.

"It's an intimidating system," ICAN's Scott said, "You almost need to bring a medical researcher and a lawyer with you to the hospital if you want to control how you give birth."

According to Zhang, "the magnitude of unnecessary C-sections at the national level is unknown." But, it is clear from his study and statements from organizations such as ACOG that too many are performed.

To curb the rise, many advocate giving women more autonomy over their labor and delivery, and combining the strengths of modern medicine with the principles and practices of midwifery.

La Follette's California office is an example of this more comprehensive approach: After participating in a larger practice for 12 years, she now works with two experienced midwives and another physician. Her practice has a successful VBAC rate of 75 percent.

"We take into account the expectations and ideas of the mom and balance that with medical guidance," La Follette said.

As more women consider practices with midwives and home births — which can be dangerous if complications arise — much of the medical establishment has been digging in its heels. In 2008, the American Medical Association's House of Delegates proposed a resolution to declare hospitals the only safe place for labor, and only midwives who work under the supervision of physicians as safe.

The Midwives Alliance of North America declared the resolution "seriously out-of-step with the ethical concept of patient autonomy in healthcare [that] distracts from other critical issues in maternity care."

If there is any chance of lowering the rates of C-sections, professional organizations will need to review all the available evidence, Zhang said.

But any change won't be easy. On the one hand, doctors need to include expectant moms in their own care; on the other, it sometimes seems that doctors who are worried about potential legal consequences can't focus on a patient's best interests.

"We're fighting a cultural issue," Scott said, that extends beyond C-sections.

She said, "We need to change the entire way we view birth and we have to be able to trust our caregivers. The alternative would be terrifying."

This article was provided by MyHealthNewsDaily, a sister site to LiveScience.