Trial of Labor after Cesarean (TOLAC)

In 2016, the US cesarean delivery rate was 31.9%. With ever increasing volumes of cesarean delivery, TOLAC has become a popular option for patients desiring vaginal delivery. On today’s episode, we examine TOLAC and share some counseling pointers in thinking about your patient. ACOG PB 205 is the requisite reading for the topic.

While there are no RCTs comparing TOLAC to planned cesarean, the relative benefits are easy to see: there is less recovery time, the patient avoids major surgery, and the potential sequelae of complications from major surgery — worsened bleeding, more opportunity for infection, more risk of complications requiring additional procedures. However, TOLAC is not without risk. We primarily counsel with respect to uterine rupture. Evaluations of “rupture” though have varied in the literature; it’s important to keep a discerning eye, as what is classified as rupture in some series is very different than what is in others. ACOG suggests the rate of uterine rupture in a patient with one low transverse cesarean delivery is around 0.5 - 0.9 %. Otherwise, maternal risks are fairly equal. Neonatal risks are also considered fairly equal, though with some increased risk associated with TOLAC.

ACOG PB 205

ACOG PB 205

We can think about patients who should be counseled against TOLAC:

  • Those at high risk of uterine rupture: ie. those with classic uterine incision, T-incision, prior uterine rupture, or extensive prior uterine fundal surgery like a myomectomy.

  • Women who are not otherwise candidates to have vaginal deliveries: ie. previa.

  • Women who desire homebirth: While ACOG does not definitely say that you cannot TOLAC in this instance, if you don’t access to emergency cesarean delivery, it is recommended that these patients have a discussion regarding the hospitals resources and possibly referral to a hospital that does have access to emergency cesarean delivery.

We can also consider patients for whom there may be a question of whether TOLAC is appropriate:

  • Low vertical incision? 

    1. Few studies, but those that have looked at them have shown similar rates of vaginal deliveries as low transverse. Can consider TOLAC!

  • Twins? 

    1. Studies show similar rates of successful VBAC in twins as in singleton gestations 

  • Obesity 

    1. Unfortunately, higher BMI seems to have an inverse relationship with success of VBAC. 85% of normal weight women achieve VBAC while only 65% of morbidly obese women do. However, morbidly obese women also can have more complications with an elective repeat cesarean, so counseling should be individualized

  • Induction and augmentation of labor 

    1. Mechanical dilation can be used - ie. cervical foley 

    2. Misoprostol has been shown to have increased risk of uterine rupture, so should not be used in term patients who have had c/s or other major uterine surgery for induction 

    3. However, in women undergoing second trimester labor inductions (ie. for missed abortion, induction of labor for stillbirths), use of prostaglandins have shown similar results in women who have had scars on their uterus and those without; so these women can still have prostaglandins, especially because no fetal considerations 

  • What if they’ve had a uterine rupture? 

    • If the site of rupture or dehiscence is in the lower part of the uterus, their risk of uterine rupture in labor is 6%. If it is in the upper segment of the uterus, the rate of dehiscence in labor is up to 32%. While there is no high quality data to guide this, recommendations are generally for subsequent pregnancies to be delivered by cesarean between 36-37 weeks.

Counseling should be individualized, and the MFMU has excellent calculators to help guide you and your patients to a decision about TOLAC:

(not in labor) https://mfmunetwork.bsc.gwu.edu/PublicBSC/MFMU/VGBirthCalc/vagbirth.html

(at admission) https://mfmunetwork.bsc.gwu.edu/PublicBSC/MFMU/VGBirthCalc/vagbrth2.html

The Evidence-Based Cesarean Section

Today we go through the steps of cesarean delivery from an evidence basis. We hope this helps everyone from the new interns starting up in just a few weeks to senior residents thinking more about their technique and teaching. The essential article on this from AJOG in 2013 can be found here. However, there have been a number of other articles and talks since, including one regularly given at the ACOG Annual Meeting (check out the 2017 edition by Dr. Strand here), that you all may be aware of and that we encourage you to check out.

One of the more challenging things to relay in the podcast is incisional technique, particularly comparing the traditional Pfannenstiel technique to newer techniques such as Joel-Cohen or Misgav-Ladach. We summarize the differences in those techniques here:

(C) CREOGs Over Coffee (2019)

What’s the difference in these skin incisions?

  • Pfannenstiel: traditionally taught as a curved incision made two finger breadths above the symphysis pubis, with the mid portion of the incision generally within the superior-most aspect of the pubic hair.

  • Joel-Cohen: a straight incision made 3cm below the imaginary line that connects the ASIS on either side. Ultimately this is slightly higher than the Pfannenstiel.

  • Maylard: curved incision made 5-8 cm obove the pubic symphysis. The rectus fascia and muscle are cut transversely, and the inferior epigastric arteries must be ligated.

  • Cherney: using the same skin incision as a Pfannenstiel, but then blunt dissection is used to identify the rectus muscle tendons at their insertion to the public symphysis. They are cut 1-2 cm above their insertion point. On closure, the muscles should be reattached to the anterior rectus sheath, as reattaching to the pubic symphysis may serve as a nidus for osteomyelitis.