In the 1970s, when the cesarean section rate tripled, the medical mantra was "once a cesarean, always a cesarean." These days, most women who have had at least one child delivered by C-section will have to decide whether to try to deliver a subsequent child vaginally . This is a decision colored by a complex set of factors, including:

  • A woman's own experience
  • The reason for the original C-section
  • Her subsequent recovery
  • Her overall health
  • Her personal preference
  • The opinion and philosophy of her doctor

What makes the decision more complex is the fact that obstetrics professionals are struggling with the issue themselves.

Reducing the C-section Rate

Cesarean section—delivery of a fetus through the abdominal wall and uterus—is considered major surgery. Blood loss during a C-section is much greater than with vaginal delivery, and the risk of serious complications like hemorrhaging and infection are also greater. Because it is not clear whether all these cesareans are necessary, the US Department of Health and Human Services has set a goal to lower the rate.

"It is generally agreed that the current national cesarean delivery rate is high, so a lot of attention has been focused on reducing the repeat cesarean rate," says Stanley Zinberg, vice-president of ACOG practice activities. "While increasing the VBAC rate will help, the overall cesarean rate can be safely and effectively reduced by reviewing the indications for primary (first) cesarean, which accounts for the majority of the national rate."

Looking at VBAC

Having a vaginal birth after a C-section (VBAC) is an area that researchers have been investigating. What are the benefits and risks? Some studies have concluded that there is not enough evidence to come up with a clear recommendation. Other studies, like the one published in the American Journal of Obstetrics & Gynecology, which included almost 18,000 women, found that VBAC is as safe as a planned C-section. But, there are risks involved with VBAC.

Women who have a vaginal birth after C-section may have a higher risk of uterine rupture. Today, uterine rupture rarely leads to loss of a mother’s or infant’s life, but it may lead to an emergency hysterectomy . This complicates a mother’s recovery and puts an end to her childbearing—a consequence that may be considerably less likely after C-section.

Examining the Reason for C-sections

The reason a woman had a cesarean in the first place often influences, or even dictates, her decision about a trial of labor for her next delivery. For example, women who undergo C-sections after long and difficult labors that did not progress may face similar difficulties with subsequent deliveries. Some of these women will choose to deliver a subsequent baby by C-section, especially if their obstetrical consultant believes the pelvis is unfavorable for vaginal birth.

C-section may be “scheduled” or “unscheduled.” A scheduled section is planned in advance. The reasons for scheduled cesareans can include:

  • Baby in breech position—When the babies head will not come out first, it is safest to deliver the baby via cesarean section.
  • Placenta previa —The placenta blocks the cervix and is at risk of detaching before the baby is born.
  • Cephalopelvic disproportion—This occurs when a baby's head is too large for the mother's pelvis. This is considered a controversial reason for C-section because the proportion is difficult to measure. Small pelvises do often accommodate large babies during labor.
  • Fetal or maternal illness—This could make labor risky for mother and/or child.
  • Previous C-section

Reasons for unplanned or emergency cesareans include:

  • Labor that fails to progress—This means labor does not progress normally.
  • Fetal distress—This, too, is controversial because fetal monitors can be misread and because "normal" is subjective.
  • Infection in the mother

Getting the Experts' View

The American College of Obstetricians and Gynecologists (ACOG) feels that women who meet the following criteria should be given the chance to try VBAC:

  • Have had one previous cesarean with a low-transverse uterine incision—You cannot tell from the outside what type of incision you had in the uterus. You need to ask your surgeon. The low-transverse incision allows muscle tissue to knit a scar that is much stronger than the older types of incisions. But, it generally takes more time to do, so doctors are not always able to use this method in emergency situations. Some women with a vertical incision may be VBAC candidates, but the evidence supporting safety in this case is less strong.
  • Have a pelvis large enough to accommodate the baby as judged by their obstetrical consultant
  • Do not have any other uterine scars or ruptures, whether from previous cesareans or other surgeries
  • If had two previous cesareans—should only attempt labor if also had previous vaginal delivery

ACOG also specifies that whenever a woman is planning VBAC, a surgical team should be on hand in case an emergency C-section is necessary. In some healthcare settings, the lack of such a team would rule out any trial of labor for a VBAC.

The American Academy of Family Physicians (AAFP) largely agrees with ACOG, but does not agree on the necessity for an on-hand emergency surgical capability. Instead, they recommend that an explicit emergency management plan be developed for all women given a trial of labor after cesarean (TOLAC). This plan should be documented, presumably in the medical record. Risks should be discussed at length with women so that they can make a clearly informed consent.

AAFP emphasizes that certain factors (age under 40, prior vaginal delivery—especially successful VBAC, obstetrically “favorable” cervix, spontaneous labor, and indication for cesarean that is unlikely to recur) make VBAC more likely after a TOLAC. They also indicate factors making successful birth less likely: gestational age over 40 weeks, birth weight over 4 kg, and need to induce or augment labor.

Making an Informed Decision

"VBAC is not risk-free, but women should also understand that elective repeat cesarean is not risk-free either," cautions Bruce L. Flamm, MD, research chairman and professor of obstetrics at the University of California at Irvine. "The key issue is choice. Once she has all the information she needs, a woman should feel good about her choice. And she should be supported in what she wants."