To VBAC or Not to VBAC? That is the Question.

One of the most controversial topics in Obstetrics is VBAC* (Vaginal Birth After Cesarean Section). Before the 1970’s, the rule of thumb was “Once a C-section, always a C-section.” When a C-section is performed, an incision is cut in the lower part of the uterus. It is sutured back together after the baby is delivered, but it is always weaker than the surrounding tissue. The concern for allowing someone to labor after a C-section is that the uterine scar might break open due to the force of the contractions. Studies in the late seventies showed that the actual occurrence of rupture was low and it was safe to consider VBAC in the appropriate candidates. With increasing C-section rates, the opportunity for VBAC increased until the mid-90’s when the VBAC rate peaked at 28%. However, with increased number of VBAC, we saw increased complications. A lot of women were getting VBACs who were not ideal candidates and at that point the dangers of induction with VBAC were not fully realized. VBAC also became a huge malpractice issue, with multimillion dollar lawsuits being handed out like candy.  The rate has continued to decline, with many physicians and hospitals no longer offering VBAC at all.

Over time, with a perpetually increasing primary C-section rate and a decreasing VBAC rate, the overall C-section rate has continued to climb at an alarming pace. The current national rate is 31%. It is truly unacceptable that 1/3 of all babies will be delivered by C-section in this country. Obviously both physicians and patients need to do what they can to reduce the primary C-section rate, but it is time to further evaluate our attitudes about VBAC.

In 2010, the National Institute of Health convened a conference to address the rising C-section rate in this country. They attempted to analyze the data and issue a newer set of recommendations to further improve patient access to VBAC. The difficulty with VBAC is that the data obtained in most studies is not of the highest quality. But based on the best available information ACOG has issued a new set of standards. The new guidelines and several journal articles this year are advocating a “common sense” approach.

So what’s the big deal with C-section anyway?
Surgery is not benign. While a commonly performed surgery, the risks of C-section are real and begin to increase exponentially with each subsequent C-section. When you have 4 or more C-sections, your chance of severe hemorrhage and complication can approach 10%, much riskier than a VBAC would have been after that first C-section. If VBACs are not available in a given region, then once a women has had one C-section, she is essentially limited in the number of children she can safely birth. There are many families whose quivers are not full at 4 children, and they desire more. Additionally, most women do not really know how many children they will want later in life. Studies show that of women who have a tubal ligation in their twenties, up to 20% of them will regret it.

A successful VBAC has the lowest risk of complication and is the best possible outcome. A planned repeat C-section is the next best, with an unsuccessful VBAC (a repeat C-section after someone has been in labor) having the highest risk of complications. A successful VBAC has many benefits for the mother including a shorter recovery time and more immediate bonding and breastfeeding with her baby. The problem is that no one can accurately predict who is going to have a successful VBAC.

The worst outcome of a VBAC is uterine rupture and it happens .5 – 1.0% of the time. This can result in serious complications for the mom including hysterectomy, hemorrhage or bladder damage. The baby can suffer neurological injury or death. The best available data shows the rate of fetal death to be 1/1000.

Best Candidates:
Prior vaginal delivery
Spontaneous labor
Non recurrent indication (cause of 1st C-section is not present in this pregnancy)

Women with spontaneous labor and a non-recurring indication have the best chance of a successful VBAC, 60-80%.

Risk factors for unsuccessful VBAC:

Maternal age >35
Maternal obesity
Fetal weight > 4000 g (8#7oz)
Pregnancy exceeding 40 weeks
Less than 18 months since last cesarean section
Induction of labor

While not deal-breakers, these risk factors make success less likely and should be considered.  A failed VBAC has the highest risk of complications, so depending on your risk factors, a repeat c-section may be the wiser choice.

Not all of these factors will be known early in the pregnancy. One option I like to use for VBAC is the ‘watch and wait.’ If a woman is a good candidate and desires to VBAC, we see how her pregnancy progresses. If she develops preeclampsia at 35 weeks and her body shows no sign of being ready for labor, then we will proceed with a repeat C-section, as induction does increase the risk of rupture. A women who’s first C-section was for breech but then has an uncomplicated second pregnancy, and goes into spontaneous labor should have a great chance for a successful VBAC.

Not Candidates:
3 or more previous C-sections
Previous classical C-section (uterine incision made in a vertical rather horizontal manner)
History of uterine rupture

I realize that this is a lot of information to process. Deciding whether to VBAC or have a repeat C-section is not always  straight forward and should be carefully considered by you and your provider. If you have a desire for more than 3 kids or have a strong desire to experience a vaginal delivery then you should more strongly consider VBAC. If you feel your family is complete with 2 kids and you are not comf0rtable with the risks of VBAC, then a repeat C-section may be your best option.

Sources:

National Institutes of Health. NIH Consensus Development Conference: vaginal birth after cesarean: new insights. Consensus Development Conference statement. Bethesda (MD): NIH; 2010. Available at: http://consensus.nih.gov/2010/images/vbac/vbac_statement.pdf.

Vaginal birth after previous cesarean delivery. Practice BulletinNo. 115. American College of Obstetricians and Gynecologists.
Obstet Gynecol 2010;116:450–63.

*For all the sticklers out there, I do realize the better term is TOLAC (trial of labor after cesarean section), but since there are aleady TMA (too many acronyms) in my post I just stuck with VBAC.