Once a Cesarean, Always a Cesarean?
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Once a Cesarean, Always a Cesarean?

Undergoing a vaginal birth after a cesarean delivery (VBAC) is a difficult and sometimes controversial decision for pregnant women who have had a previous cesarean section.

Every woman's experience of labor and delivery is unique. Cesarean childbirth, it turns out, is no different. 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 physician

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

Reducing the C-section Rate Through VBAC

Cesarean section—delivery of a fetus through the abdominal wall and uterus—is considered major surgery and accounts for more than 26% of American childbirths. Blood loss during a Cesarean 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.

Since repeat cesareans account for one-third of the cesarean rate, there is an effort underway to encourage women who have had a previous C-section to try delivering vaginally whenever possible. Some managed care plans and insurers actually require a trial of labor, much to the consternation of obstetricians and many of their patients. However, a survey conducted last year by the Maternity Center Association found that more than 40% of women with a history of C-section were denied the option of a vaginal birth.

VBAC Has Risks, Too

Although studies show that the vast majority—some 60% to 80%—of VBAC's are successful, enthusiasm for VBAC has recently been tempered. In the late 1990s, the American College of Obstetricians and Gynecologists (ACOG) published a practice bulletin strongly encouraging VBAC, but urging caution.

In their bulletin, ACOG warns that VBAC carries its own potential risks and financial costs, including the risk of uterine rupture. ACOG underscores that increasing the VBAC rate is not the only way to lower the cesarean rate, and stipulates that the decision be left to a woman and her doctor. Uterine rupture today only rarely leads to loss of a mother’s or infant’s life, but it often means that an emergency hysterectomy must be done. This complicates a mother’s recovery and obviously puts an end to her childbearing–a consequence that may be considerably less likely after cesarean section.

"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."

Why a C-section?

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 didn't progress may face similar difficulties with subsequent deliveries. Some of these women will choose to deliver a subsequent baby by Caesarean section, especially if their obstetrical consultant believes their pelvis is deformed or otherwise unfavorable for vaginal birth.

Some women have a first Cesarean without any labor experience at all. Statistically, however, women without any labor experience are less likely to have successful labor than women who have labored before their cesarean. This is especially true for women who deliver a premature baby by cesarean section but without any significant labor prior to surgery.

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

  • Baby in breech position. Though some physicians will allow women to deliver breech babies vaginally, the rate is low, especially for first-time mothers. A subsequent baby is unlikely to also be breech.
  • Placenta previa. The placenta blocks the cervix and is at risk of detaching before the baby is born; this condition is unlikely to repeat itself in a subsequent pregnancy.
  • Cephalopelvic disproportion. 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 and because small pelvises do often accommodate large babies during labor.
  • Fetal or maternal illness. This could make labor risky for mother and/or child.
  • Previous cesarean. The mother has delivered a previous child via C-section.

Reasons for unplanned or emergency cesareans include:

  • Labor that "fails to progress" (dystocia). Fetus is in distress despite prolonged active labor, or labor doesn't progress normally. This, too, is controversial because fetal monitors can be misread and because "normal" is subjective.
  • Fetal distress
  • Infection in the mother

Experts' Take on Candidates for VBAC

Here's who as of February, 2006, ACOG thinks should be offered a chance to try VBAC:

  • Most women who have had 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. This 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 perform, so physicians aren't 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.
  • Women with a pelvis large enough to accommodate the baby as judged by their obstetrical consultant.
  • Women without any other uterine scars or ruptures, whether from previous cesareans or other surgeries.
  • Women with two previous cesareans should only attempt labor if they have had a previous vaginal delivery as well.

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 such as smaller hospitals or birth centers, the lack of such a team would rule out any trial of labor for a VBAC. Unlike some of the recommendations above, the recommendation for emergency surgical team availability is based on expert consensus rather than solid evidence.

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.

The Society of Obstetricians and Gynaecologists of Canada has also released clinical practice guidelines on VBAC. These guidelines are quite similar to those of ACOG, though they state explicitly that in Canada the appropriate availability of emergency C-section is defined as “an approximate time frame of 30 minutes.”

A Personal Decision

A large part of the decision is up to the woman, and that means she must be well-informed about VBAC.

"One thing today is patient choice. I think it's been misconstrued in recent years," says Bruce L. Flamm, MD, research chairman and professor of obstetrics at the University of California at Irvine and author of Birth After Cesarean: The Medical Facts. "The situation is going to be different for every woman. It depends very much on the woman and on her situation. The key thing is counseling."

As part of a California task force working to lower the cesarean rate, Dr. Flamm has worked hard to make sure women and physicians understand the risks of cesarean surgery. He strongly believes that the cesarean rate is too high. Still, he believes that an informed woman who chooses to have a repeat cesarean should absolutely have that option.

"VBAC is not risk-free, but women should also understand that elective repeat cesarean is not risk-free either," Dr. Flamm cautions. "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."

RESOURCES:

American College of Obstetricians and Gynecologists
http://www.acog.org

Childbirth.org
http://www.childbirth.org

CANADIAN RESOURCES:

The Canadian Women's Health Network
http://www.cwhn.ca/indexeng.html

The Society of Obstetricians and Gynaecologists of Canada
http://sogc.medical.org/

References:

American College of Obstetricians and Gynecologists website. Available at: http://www.acog.org.

Childbirth.org website. Available at: http://www.childbirth.org.

Society of Obstetricians and Bynaecologists of Canada. SOGC Clinical Practice Guidelines. Int J Gynaecol Obstet. 2005;89:319-331.

Trial of labor after Cesarean (TOLAC), formerly trial of labor versus elective repeat cesarean section for the woman with a previous cesarean section. American Academy of Family Physicians website. Available at: http://www.aafp.org/PreBuilt/clinicalrec_tolac.pdf. Accessed February 9, 2006.



Last reviewed May 2008 by Jeff Andrews, MD, FRCSC, FACOG

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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