Concerns About the Safety of Vaginal Birth After Cesarean (VBAC)

concerns about the safety of vaginal birth after Cesarean (VBAC)As a childbirth educator I am not a medical care provider and am not qualified to diagnose, prevent or treat any condition. So, do my opinions on VBAC even matter? Well yes, but only because I am listening to the experiences and preferences of my clients and also because I am closely following the available research on this subject. I recently completed the Due Dates and Advanced Maternal Age course with Evidence Based Birth. While my role is not to advise anyone on the best course of action, I do hope to express a balanced perspective that may help people who have concerns about the safety of vaginal birth after Cesarean (VBAC).

Here is a common scenario: a couple is pregnant with their first baby and have chosen an obstetrician for their prenatal care. There is no reason to question or seek another opinion about anything that is said. The MD’s degree makes him or her an expert on all things related to birth, right? The pregnancy moves along well. There are no concerns. Long about the 39th or 40th week of pregnancy things shift a little, not in the form of anything overly concerning, but the doctor says something about either the baby getting too big or the pregnancy potentially going on too long potentially causing problems for the baby. As first-time parents, we don’t take any chances, so we may go along with the recommendation to induce labor a few days past 40 weeks or at the very latest, a few days past 41 weeks. The induction goes OK at first but about 24 hours in, the baby becomes distressed and an emergency Cesarean is performed.

Are the doctor’s concerns at the end of pregnancy totally unwarranted in this very common scenario? No, not entirely! So we shouldn’t assume that there is something inherently wrong about their clinical opinion. However, there are a few contrary points to consider:

  • Due dates. How was your due date set? Was it done by an early ultrasound (between 8 and 12 weeks) or was it based on last menstrual period (LMP)? An early ultrasound is more accurate in determining gestational age. If you arrive at a sense that maybe your due date was off and you actually hadn’t reached 40 weeks gestation yet, would you have felt differently about inducing?
  • Your body. Consider your own cycle. Is it like clockwork? Is it almost always consistently 28 days? This is relevant because of the time involved as well as hormonal considerations. Some people need a bit more time than average to gestate.
  • Clear medical reasons to induce. There are valid reasons to induce, namely the presence of gestational diabetes, high blood pressure and protein in the urine (pre-eclampsia), intrauterine growth restriction (IUGR), or a pregnancy that has reached 42 weeks. Diagnostic testing is fairly accurate for these conditions, though it should be noted that in certain cases the risk of inducing might still outweigh the risk of waiting. Examples of this would be elevated blood pressure in the absence of protein in the urine which resolves when anxiety is lessened, a baby that is small but not necessarily very small for gestational age, or a pregnancy that has reached 42 weeks in the absence of any problems with the pregnancy (fluid levels and placenta are excellent and the baby and mother are in excellent health).
  • Unclear medical reasons to induce. A pregnancy length that is estimated to be between 41 and 42 weeks with good (but not excellent) biophysical profile results. In other words, there may be some calcifications on the placenta or the fluid may be on the low end of normal. The research does not support induction for either of these findings by itself (however both of these findings together might be a reason to consider inducing). As far as the baby’s size, there is simply no test available that will determine with complete accuracy whether a baby will fit through a pelvis. A baby that is suspected to have reached 11 lbs. in the absence of gestational diabetes might point towards some (hopefully gentle) induction techniques, however there is no way to know whether a baby will fit or how big the baby is until the mother is pushing and the baby is placed on the scale. And keep in mind that many shoulder dystocias (the major concern as it relates to large babies) are more easily resolved when a mother has freedom of mobility. Hypnobabies is an excellent tool which helps so many of my clients do so well without epidurals! And shoulder dystocias are relatively rare even though most birthing people in the general population do use epidurals.

In practice, many doctors prefer to induce their patients between 41 and 42 weeks because the evidence does support this as prevention of a few cases of stillbirth (approximately a 1 in 1,000 risk, which could rise sharply if you are considered advanced maternal age), but your absolute risk (versus relative risk) may be much lower. Obviously doctors are rightfully very concerned about the possibility of a stillbirth (fetal demise) if the health of a pregnancy deteriorates. But it’s important to know that doctors must induce almost 500 patients unnecessarily in order to prevent 1 case of fetal demise. It’s up to the individual to evaluate their absolute risk.

Now that we have covered the induction piece, where do we go from here? We had a Cesarean with our first birth, possibly because of an unnecessary induction, and we might feel that we would really like to try to experience a vaginal birth for one reason or another. Is it out of the question? The reason that many doctors do not practice in a way that is highly supportive of VBAC is that they are not willing to take on any additional risk. The risk we are concerned about as it relates to VBAC is uterine rupture. Not words that a pregnant person wants to hear. The risk is real however small (0.4%). If uterine rupture happens, an emergency Cesarean will be needed or the baby is in grave danger.

Can we manage this risk appropriately? Yes, there are ways to do so. Keep in mind that approximately 99.6% of VBACs will happen without uterine rupture occurring; if it does occur, getting to the OR safely and quickly is very likely. Our baby helps us to manage this appropriately by showing us a happy heartbeat. A happy heartbeat during labor lets us know that our baby is doing well and enjoying the labor. If a baby is not enjoying the labor, it can be a definite sign that it’s time to be born quickly and a Cesarean birth is a way to achieve that goal. So for VBAC, listening to the baby’s heartrate more often or even continuously during active labor is advised. Also, if a mother is feeling sharp pains in the uterus not related to contractions, this is also a sign that uterine rupture may be occurring and a swift Cesarean would be advisable.

So the final point that I would like to make here is that there is a difference between a provider who is supportive of VBAC versus one merely providing a TOLAC (trial of labor after Cesarean). I don’t care for that language because in birth we look to Yoda: there really is no “try.” Only do or do not. And if we’re going to do VBAC it’s important to support it in as many ways as we can. So that means encouraging the normal process so long as mother and baby are healthy, just as we prefer to do for first pregnancies. (You should also know that the research does support gentle inductions for VBAC patients when medically warranted.) And this also means providing access to continuous monitoring options that allow for freedom of movement and water immersion (so portable, wireless, and waterproof). This allows us the best chance to find comfortable and safe positions for labor that utilize gravity to help our babies descend!

If you are interested in pursuing VBAC for your birth, I highly recommend selecting a care provider who is highly supportive of that option. Midwifery care through Loudoun Community Midwives at StoneSprings Hospital, GW Midwives in DC, or the NOVA Natural Birth Center in Chantilly would all be excellent choices. But if you’re more of a “worry wart” and your concerns about the safety of VBAC would be better managed by an obstetrician, I recommend Dr. John Gonzalez at Prince William Hospital. I hear that his Cesarean rate is only 4% and that the hospital’s rate is 8%! This definitely indicates a VBAC-supportive environment. I also recommend a great class and doula support to ensure that you have as many tools available to you and as much support surrounding you as possible. I hope this has been helpful and best wishes as you prepare for your birth!

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