Vaginal birth after cesarean (VBAC): Clinical sciences

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Introduction0:00–0:41

.Vaginal birth after cesarean, also known as VBAC, refers to a successful vaginal delivery in a patient with a prior C-section.
While many patients may choose to undergo a trial of labor after cesarean, also known as TOLAC, to avoid the risks of major abdominal surgery, others may elect for a repeat C-section due to the increased operative risks with an intrapartum C-section compared to a planned one.
Ultimately the decision must be individualized but it is important to know the risks, benefits, and contraindications, so you can provide your patient with the best information to make their decision.The first step when a patient presents desiring a TOLAC is to perform a focused history and physical examination, …with particular attention to their obstetric history.

Focused History 0:41–3:39

This means obtaining the past operative note to know what kind of C-section they had. The most common type of C-section is one where a low transverse incision is made in the lower uterine segment of the uterus to deliver the infant.
However, sometimes a classical C-section is performed where a vertical incision is made in the contractile portion of the uterus.
This is important because TOLAC is not recommended for a patient with a prior classical C-section, due to a higher risk of the uterus rupturing during labor.
Patients with a history of an extreme preterm delivery, a history of significantly large fibroids, or a history of a difficult extraction of the infant may have had a classical C-section.
Here are a couple of clinical pearls! You can’t determine the type of uterine scar by looking at the direction of the skin incision.
Sometimes vertical skin incisions are made while the uterine incision is low transverse; alternatively, a patient may have a low transverse skin incision but their uterine incision is vertical, meaning it’s classical.
Additionally, some types of uterine surgery should be treated as if the patient had a classical C-section. This happens when incisions are made into the contractile portion of the uterus, such as when removing large intramural leiomyomas during a myomectomy.Okay, back to your patient.
You’ll also want to know the number of prior C-sections. The risk of uterine rupture increases with each previous C-section.
Generally, TOLAC is considered safe with one or two prior C-sections, though this may vary by provider comfort. It’s also helpful to know the indication for the prior C-section.
Patients who have previously had an arrest of dilation or descent are less likely to have a successful VBAC. Alternatively, a patient who had a C-section for breech or for non-reassuring fetal assessment could be more likely to have a successful VBAC, simply because they haven’t been able to truly labor before.
Also ask your patient about prior vaginal births, because a prior vaginal birth, either before or after their C-section, will also increase the odds of successful VBAC.
Be sure to find out when the C-section was performed, as an interval of at least 18 months is ideal to allow the uterine scar to fully heal.
Other things worth considering are age, height, prepregnancy weight, and history of hypertension, as these impact the chances of successful VBAC.
Remember, these historical factors can only help provide an estimate of the chances of success if your patient decides to attempt a VBAC.
Ultimately each patient has to make their own decision, but providing an estimate of their odds for a successful trial of labor will help to prevent the complications associated with an intrapartum C-section.Now, if your patient has a contraindication to TOLAC, such as a prior classical C-section, more than two prior C-sections, or any contraindication to labor in general, perform a repeat C-section when delivery is indicated.On the flip side, if there are no contraindications to TOLAC, there are many things to discuss when planning delivery.

Contradictions to TOLAC3:39–3:58

No Contraindications to TOLAC3:58–6:47

You need to review the risks and benefits of both TOLAC and planned repeat C-section with your patient. A planned repeat C-section carries all the risks that come with a major abdominal surgery.
Each C-section tends to become more difficult due to increased scar tissue. Patients should also be made aware that each C-section increases the odds of abnormal placentation in future pregnancies, that carries significant morbidity, such as placenta previa and placenta accreta spectrum.
On the other hand, a VBAC can lead to a shorter hospital stay, lower rate of hemorrhage and infection, and minimize the risks of maternal consequences of multiple C-sections, such as the formation of adhesions that can make both obstetric and non-obstetric surgery more difficult.
Remember, there’s no guarantee a TOLAC will lead to a VBAC, and TOLACs carry their own risk, with the most feared one being uterine rupture which is when the scar on the uterus opens in labor.
Uterine rupture carries substantial morbidity and even mortality to both the patient and the fetus. So even though it is rare, it must always be discussed.
And remember, we can’t know for sure who will have a vaginal delivery if they opt for a TOLAC and who won’t. If TOLAC is undertaken and fails, then you must perform an intrapartum C-section.
TOLACs, in general, have been shown to potentially carry more neonatal morbidity, likely due to the risks when uterine rupture occurs, and due to difficult C-sections performed for intrapartum indications.
Intrapartum C-sections carry a higher risk of infection due to exposure to vaginal flora, as well as increased risks for surgical injury and need for transfusion because they are technically more difficult.
The risks of intrapartum C-section can be minimized by performing a scheduled C-section rather than attempting a trial of labor.
A scheduled C-section has a lower risk of uterine rupture since it avoids the stress of labor, but the risk isn’t absent since uterine rupture can spontaneously occur before the C-section.
Also, if your patient desires surgical sterilization, there is the benefit of being able to perform that at the time of C-section.
So, based on all of your patient’s previous history, you can provide an estimate of successful VBAC, with the average rate of success being about 60 to 80%.
Once your patient feels they understand the risks and benefits of TOLAC, they can make their decision. If they decline TOLAC, proceed with a repeat C-section.
Alternatively, if they desire TOLAC, you can move on to delivery planning.It is important to point out that TOLAC carries a little more risk than laboring without having a prior C-section.

Delivery Planning6:47–8:04

So, it is important to make sure both you and your patient are prepared for delivery. Now, labor induction is not contraindicated in those with a history of a C-section.
However, prostaglandins, such as misoprostol, must be avoided because of the increased risk of tachysystole and uterine rupture.
While oxytocin can be used, you’ll want to minimize how much and for how long, because of the correlation between the amount used and uterine rupture.
Next, continuous fetal monitoring is recommended because the first sign of rupture is usually non-reassuring fetal assessment.
You should also have IV access in place in case of a need to perform an emergent C-section. In fact, it is generally accepted that a requirement for a facility to offer TOLAC is the ability to perform an emergent C-section.
This means having both an anesthesia and surgical team in-house. If a facility can’t provide these things, VBACs should not be performed at that location.
Finally, as with other patients in labor, the standard indications for C-section and operative vaginal delivery, such as arrest disorders or fetal malpresentation, remain the same.Alright, as a quick recap...

Review8:04–8:36

When a patient presents desiring a TOLAC, you should obtain a history and physical exam and consider contraindications. If your patient has a contraindication to TOLAC, such as a prior classical C-section, more than two prior C-sections, or any contraindication to labor in general, perform a repeat C-section.
However, if no contraindication exists, review the risks and benefits of both repeat C-section and TOLAC with your patient.
For any TOLAC, perform continuous fetal monitoring, have an IV in place, and avoid prostaglandins if an