A Woman's Guide to VBAC: What We Don't Know

By Amy Romano

This article is part of A Woman's Guide to VBAC: Navigating the NIH Consensus Recommendations, a collection of resources that address the most common and pressing questions women may have about their birth choices. View all sections in the guide, including a link to the authors, on the index page.

The NIH Consensus Conference Panel set out to review and publicize the evidence (research) to help women make informed choices between planned VBAC and planned repeat cesarean. Their review revealed that most of the research has focused on short-term outcomes such as bleeding, infection, and length of hospital stay and serious events such as uterine rupture, hysterectomy, and newborn death or serious injury. Much less attention has been given to longer-term outcomes or to the modifiable factors (such as care in pregnancy and labor) that can produce the best health outcomes for mother and baby and make VBAC - or for that matter, repeat cesareans - safer.

The Panel identified ten critical gaps in the evidence, which can be reviewed in full in this section of the Panel's recommendations: http://consensus.nih.gov/2010/vbacstatement.htm#q6.

This article will take a closer look at several of these gaps, and suggest strategies for making the best choice possible in the absence of good research.

What is the safest way to care for a woman in labor with a scarred uterus? Your likelihood of safely achieving a vaginal birth should you plan a VBAC is affected by some factors that cannot be changed, such as your general health, whether you have had a prior vaginal birth, and the reason for your prior cesarean. But it may also be affected by factors that can be altered by your care providers, your birth setting, your support team, and your choices in labor. Surprisingly, almost no research has been conducted to define the best way to care for women in VBAC labors.

What you can do in the absence of good evidence: Until that research is available, women may need to rely on research about safe practices in any labor, plus some common sense. Try to make choices that keep you and your baby safe and are associated with a higher chance of vaginal birth, such as:

  • Use a midwife for your care, or if none is available, choose a doctor with a low cesarean rate and a high VBAC rate.
  • Avoid induction of labor unless there is a clear need.
  • Plan for excellent labor support, including a doula if possible.
  • Walk, move, and change positions in labor as much as possible.
  • Plan to use a variety of strategies to cope with pain before considering an epidural, including a tub or shower, position changes, relaxation techniques, and massage or counter-pressure.
  • Stay well nourished and hydrated.
  • Follow your own urge to push and stay off your back when pushing.

Women without a prior cesarean can also reduce their chance of a c-section by staying home in early labor and having intermittent (periodic) monitoring of the baby's heartbeat in labor. These recommendations are more controversial for women with prior c-sections. Many care providers, concerned about the small possibility of uterine rupture and their professional liability should it occur, will insist that a woman with a scarred uterus come to the hospital as soon as regular contractions begin and that the fetal heart rate be continuously monitored after hospital admission. There is no evidence that coming to the hospital early in labor is safer than encouraging the woman to experience early labor in their own home, and it is very likely to increase the chance of a cesarean by setting into motion the cascade of interventions and putting you on the clock. If you do stay home in early labor, have someone there to give you continuous physical and emotional support and call your care provider if you have any symptoms that concern you.

Continuous electronic fetal monitoring (EFM) increases the chance that a low-risk woman will have a c-section, but no research tells us if the same is true in VBAC labors, nor under which circumstances, if any, continuous EFM improves health outcomes for the baby in VBAC labors. An abnormally slow fetal heart rate is the best indicator that the woman's uterine scar has ruptured or is about to rupture, and continuous monitoring can detect a slow heart rate quickly. But early diagnosis of a problematic fetal heart rate pattern may not always alter the outcome - some babies may still be injured no matter how early the diagnosis and other babies may be OK even if the diagnosis is delayed. In the absence of conclusive evidence, most care providers will recommend or insist on continuous EFM and many women may feel safer with continuous monitoring. If you have continuous fetal monitoring, ask for cordless (or telemetry) monitoring that allows you to move around. Most hospitals have water-proof fetal monitoring equipment so you may be able to use a shower or tub for pain relief even with continuous monitoring.

What are the long-term outcomes for mothers and babies after VBAC, unplanned repeat cesarean, and planned repeat cesarean? Not enough research is available to provide a full picture of the long-term benefits and harms of different birth routes.

By far, most of the evidence from long-term studies or observations favors planned VBAC. Women who plan and achieve a VBAC have the best long-term health, in part because they avoid the known increased risks of placenta accreta, placenta previa, and hysterectomy should they become pregnant again. (These risks are reviewed in this section of the guide.) We have less evidence for other long-term outcomes, but the evidence we do have suggests that planned VBAC may also reduce the likelihood of:

  • chronic pain
  • subsequent ectopic pregnancy
  • stillbirth in a subsequent pregnancy
  • infertility
  • complications during subsequent abdominal or pelvic surgeries, including surgical adhesions (which may make the surgery and the recovery more difficult), significant bleeding, and injuries to the bladder, ureters, and bowel.

On the other hand, although the overall likelihood of injury to the baby is low whether a woman plans a VBAC or a repeat cesarean, more babies experience brain or nerve injuries during VBAC labors than during planned repeat cesareans, and some of these injuries have long-term consequences. The researchers found no studies that measured the impact of planned VBAC versus planned repeat cesarean on the long-term neurologic development of infants.

The researchers tried to determine if planned repeat cesarean protected pelvic floor strength and function. They found no studies that looked at this issue, and state that the body of literature that suggests that primary (first birth) elective cesarean delivery offers a modest, short-term benefit to the pelvic floor may not apply to women considering repeat cesarean delivery. This is because, unlike a woman considering a cesarean for her first birth, women considering repeat cesareans have had prior pregnancies and may have had prior labors, both of which alter the pelvic floor muscles.

What you can do in the absence of good evidence: It is reasonable to incorporate these findings into your decision-making even though they come from studies that are not as strong as they could be. It is clear that for women who may go on to have more children, a history of multiple cesareans increases risks substantially in subsequent pregnancies. Therefore, you should strongly consider a VBAC if you think there is a chance you might become pregnant again in the future. Even if you do not plan to have more children, you should be aware of risks for future pregnancies. Many women change their mind about becoming pregnant again or decide to carry an unplanned pregnancy.

What approach to decision-making, what care around the time of birth, and which planned mode of birth protect and promote the psychological and emotional wellbeing of mothers, infants, and families? The researchers found no studies that address psychological or emotional outcomes.

What you can do in the absence of good evidence: Even though there is no research specific to women with prior cesareans, research generally suggests that you are the least likely to suffer emotionally or psychologically when you:

  • participate actively in your care
  • have care providers who are responsive to your needs and desires
  • have good emotional support around the time of birth and in the days and weeks after the baby is born.

On the other hand, unexpected serious outcomes, such as death or injury to the baby or a hemorrhage requiring hysterectomy, can cause emotional suffering that can sometimes be debilitating and long-term. Serious outcomes are least likely in women who successfully birth vaginally, so strategies that safely increase the likelihood of vaginal birth in women planning a VBAC may protect emotional and psychological wellbeing as well.

If you experience emotional distress after birth, reach out to support groups in your community or online. Solace for Mothers, the International Cesarean Awareness Network, and Postpartum Progress are great resources.

What is the effect on breastfeeding of VBAC, unplanned repeat cesarean, and planned repeat cesarean? The researchers found no studies that address breastfeeding rates or the likelihood and severity of breastfeeding problems.

What you can do in the absence of good evidence: Be aware that it is very likely that VBAC will increase the ease with which you will be able to breastfeed, since vaginal birth and breastfeeding are part of a biological continuum. In addition, in most settings, cesarean surgery necessitates at least a brief (and sometimes prolonged) separation between mother and baby, which is known to disrupt breastfeeding, and postoperative pain may make early breastfeeding difficult.

Also be aware that with excellent lactation support and patience, breastfeeding difficulties related to cesarean surgery can usually be overcome. Whether you plan a vaginal birth or a repeat cesarean, discuss with your care providers your desire to minimize separation from your baby, including strategies for keeping your baby with you or your partner should you have a cesarean. If possible, give birth in a setting that adheres to the standards of the Baby-Friendly Hospital Initiative.


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