how long after a c section can you have a vbac?

VBAC Facts: Is Vaginal Birth After Caesarean Right for You?

Here | s what to ask your health care provider.

If you | re pregnant and you | ve previously had a cesarean section, you may have a decision to make: Do you try for a vaginal birth after cesarean (otherwise known as a V.B.A.C.) or schedule another cesarean?

Deciding whether or not to try for a V.B.A.C. means reckoning with the details of your medical situation in the context of your values, according to the experts. Some women may want the experience of labor or a vaginal delivery but may need a cesarean because medical issues stand in the way. Others don | t mind another cesarean.

“I think it | s important to know that V.B.A.C. is an option for most women, and their chances of success are actually quite high,” said Dr. Jeanne-Marie Guise, M.D. M.P.H., professor of obstetrics and gynecology at Oregon Health & Science University School of Medicine. According to the 2010 consensus statement by the National Institutes of Health, women attempting a V.B.A.C. have a 74 percent chance of a vaginal delivery.

However, planning a V.B.A.C., or even another cesarean, offers no guarantees that delivery will go according to plan.

Danielle MacIsaac, a stay-at-home mom of three with a small knitting business in Canton, Mass., decided to try for a V.B.A.C. with her second child but ended up needing a repeat cesarean when one of the issues she had with her first delivery arose again.

On the other hand, Beth Houlihan, an office manager and mom of two in Los Angeles, had a cesarean with her first child because he was breech. Though she | d scheduled a cesarean with her second, she went into labor spontaneously at 37 weeks and 3 days, almost delivering in the hospital parking lot.

If you | re considering a V.B.A.C., discuss the following questions with your health care provider before deciding the right course of action for you:
Are you a candidate for a V.B.A.C.?

If you | ve had only one (or sometimes two) previous cesareans, you might be a candidate. You | re a candidate if the cesarean scar on your uterus is horizontal and low, called a low transverse incision. Low transverse incisions are now standard in the United States. The scar on your skin doesn | t necessarily communicate the placement of the incision on your uterus; your medical records provide more accuracy.

[Read: what to expect from a cesarean section.]

The American College of Obstetricians and Gynecologists generally recommends that everyone wait at least 18 months between pregnancies. If you become pregnant 6 months or less after your cesarean, the risk of uterine rupture, one of the potential complications of a V.B.A.C., is higher. In this case your provider may recommend against a V.B.A.C.

The reason for your previous cesarean matters, too. If your previous cesarean was because of what doctors refer to as “non-repeating factors,” or circumstances that don | t have a high chance of recurring — such as breech birth, twins, placenta previa (placenta covering the cervix) or placental abruption (placenta detaching from the uterine wall) — you | re a candidate for a V.B.A.C. You may or may not be a candidate if you had a cesarean because of other factors – if your labor stalled, you stopped dilating or you pushed for a long time and the baby didn | t come out. Whether or not these factors are likely to repeat depends on your situation and is something to discuss with your provider. I had a cesarean for a placental abruption, a non-repeating factor, which means that I would theoretically be a V.B.A.C. candidate.

You are not a candidate for a V.B.A.C. if your baby is breech (unless your providers can successfully rotate the baby before labor) or if you develop placenta previa.

Many, but not all, hospitals and birth facilities offer V.B.A.C.s, though they typically offer them only if obstetricians and anesthesiologists are on call to respond if you need a cesarean. In the appropriate birth facility, both midwives and obstetricians can supervise V.B.A.C.s.
What are your chances of a vaginal delivery if you try for one?

While 74 percent of women who attempt a V.B.A.C. are successful in having a vaginal delivery, many factors can influence that success. One of the strongest variables in your favor is having had a previous vaginal delivery; and having had a previous V.B.A.C. can increase your chances even more, said Dr. Guise. Being taller, younger and having a body mass index below 30 are also associated with greater chances of a V.B.A.C., according to the 2010 N.I.H. statement.

If you | re older, shorter, Hispanic, African-American; or if you have certain health conditions like high blood pressure, diabetes, asthma, seizures, kidney disease, thyroid disease, heart disease or obesity, your chances of success are lower. Using Pitocin to induce labor is also associated with lower chances of V.B.A.C. success, as is having a baby weighing more than 8 pounds, 13 ounces.

But a chance is not a certainty, and different factors affect your chances to different degrees. You can calculate your odds using this calculator developed by the National Institutes of Health. (If you are both African-American and Hispanic, the calculator will not allow you to select both, because the research used to build it did not include enough women who fit in both categories to draw valid mathematical conclusions, said Dr. William Grobman, M.D., vice chair for clinical operations in obstetrics and gynecology at Northwestern University, who led the research used to build the calculator.) As you approach your due date – or if you go into labor at an unexpected time – your provider can recalculate your chances using new information (for example, whether your cervix is dilated or whether you have been induced).
What are the risks and benefits of trying for a V.B.A.C.?

Having a V.B.A.C. generally means your recovery will be shorter and easier than having a repeated cesarean section. There | s also lower risk of blood loss and other complications. If you want to have more pregnancies, having a V.B.A.C. is better for your future deliveries because it reduces the risk that the placenta will implant on your cesarean scar (a form of placenta accreta) in future pregnancies. Placenta accreta makes it harder to get the placenta out during delivery and can result in hemorrhage and, in the most severe cases, a hysterectomy. Also, cesarean section surgeries can be more difficult on average with each subsequent delivery because of scar tissue.

On the other hand, your risk of uterine rupture with a V.B.A.C. is slightly higher than your risk of a rupture with a planned repeat cesarean, according to the N.I.H. statement — though the chance of this happening is low. If your uterus does rupture, you | ll need an emergency cesarean. If you don | t get to the operating room quickly enough, there is a small chance that a lack of oxygen may damage your baby | s brain, and in 6 percent of uterine ruptures, the baby dies. For the mother, a uterine rupture carries a risk of blood loss and a 14 to 33 percent chance of a hysterectomy. If you end up needing a cesarean after some time in labor, you have a higher risk of complications, such as bleeding and infection, than you would with a planned cesarean.

If you do try for a V.B.A.C., “having an epidural can be helpful” because it will smooth the transition to a cesarean if one is necessary, said Dr. Guise. If you already have an epidural, you are less likely to need general anesthesia, which often means your support person can be in the operating room with you.
What are the risks and benefits of a planned cesarean?

If you | re having a planned repeat cesarean, your risk of uterine rupture won | t increase, and you | ll have a lower risk of complications (such as bleeding and infection) than if you ended up getting a cesarean after some time in labor. So if you | re likely to need a cesarean anyway (that is, if your chances of V.B.A.C. success are low), it may make sense to choose the less risky planned cesarean instead of going into labor. A planned delivery date is also easier to schedule around.

On the other hand, as with all births, there | s a risk of infection, blood loss and even death. The risk of maternal death during a planned cesarean is low, but higher than the risk of death during a V.B.A.C. (a 13 in 100,000 risk during a planned repeat cesarean compared to 4 in 100,000 for a V.B.A.C.), according to the N.I.H. statement. Cesarean recoveries are usually longer and make the early postpartum weeks more challenging than vaginal delivery recoveries do. (For example, you can | t lift anything heavier than your newborn, you | re usually told not to drive and climbing stairs can be challenging.)
Could you make a contingency plan?

Obstetricians and midwives know better than anyone that labor and delivery don | t always go as expected. Your provider may be happy to discuss a contingency plan if, at some point during your pregnancy or labor, you decide you no longer want to try for a V.B.A.C. and want to have a planned cesarean. “It | s O.K. to change your mind,” said Dr. Melissa Avery, Ph.D., C.N.M., a professor of nursing and midwifery at the University of Minnesota.

A contingency plan could be something like:

If I go into labor on my own, and my chances of a V.B.A.C. look decent, I | d like to try for one. If at 40 or 41 weeks I have not gone into labor and I | m not dilated at all, or if my chances of a V.B.A.C. look worse than we expected, I | d like to have a cesarean rather than inducing labor and trying for a V.B.A.C.

For example, MacIsaac had planned to have a cesarean rather than try for a V.B.A.C. if she reached 42 weeks without going into labor spontaneously, because she and her doctor felt it was too risky to induce her. “I knew that there was a risk that I would have a C-section,” she said. “The doctors and midwives were very clear with me.”

Houlihan had not discussed an alternate plan for her scheduled cesarean with her obstetrician, but she followed an impromptu one anyway when she went into labor earlier than expected. By the time she and her husband were driving to the hospital, running red lights, labor was intense. “My hands are on the windshield and I | m screaming,” she said. In the hospital parking lot, “I get out of the car and I go, | Oh s—-, I have to push. | So I put my hands on the car and I push, and her head popped out,” said Houlihan. Houlihan had an accidental V.B.A.C. in the hospital shortly afterward.
Which choice aligns with your values?

When discussing a mother | s odds of having a successful V.B.A.C., Dr. Avery said it | s important to consider not just the best available evidence but also her patient | s values. “How each individual person considers risk is important,” she said. One person might value having more children in the future, while another might value minimizing the risk of surgical complications. “It | s an ongoing process.”