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INTRODUCTION/BACKGROUND

KEY QUESTIONS

  • Who is an appropriate candidate for a trial of labor after cesarean section (TOLAC)?

  • What are the risks associated with a TOLAC?

  • What tools are available to help evaluate a patient's likelihood of successful vaginal birth after cesarean (VBAC)?

  • What methods of labor induction are available for patients who request a TOLAC?

CASE 52-1

A patient arrives to your triage area complaining of leakage of fluid at 37 weeks gestation. She reports that she thinks she has been leaking for about the past 8 hours. Her prenatal chart reveals that she has had minimal prenatal care. It also states that her previous delivery was a C-section for beech presentation at term. Her cervical exam reveals she is 2 cm dilated and 50% effaced, with the head at ‒2 station. The contraction monitor shows minimal activity. FHR analysis is reassuring and reactive. There is no evidence of any discussion regarding the mode of delivery during her prenatal visits. How should you proceed?

Given the current cesarean section (C-section) rate, the prevalence of patients with a prior cesarean delivery is very high. Data processed from 2014 reveals a global average C-section rate of 18.6%, with particular countries having exceptionally high rates, such as Brazil (55.6%) and the Dominican Republic (56.4%).1 The United States currently has a rate of 32.2%, well above the average.2 Consequently, the number of patients who are potentially eligible for a TOLAC in a subsequent pregnancy is also increasing.

For patients requesting a TOLAC, the initial task is to assess if they are appropriate candidates for the procedure. Ideally, this evaluation would take place over the course of the patient's prenatal care, involving information gathering and thorough discussions. Factors specific to the current pregnancy, the previous cesarean delivery (or deliveries), and the patient's preferences and risk tolerance should all be considered. However, for any number of reasons, sometimes this evaluation has not been completed prior to the patient arriving at the hospital. Therefore it is critical that an obstetrics and gynecology (OB/GYN) hospitalist be able to perform an assessment of each patient's situation, sometimes in rapid fashion, and formulate a plan that is appropriate for the patient, provider, and facility.

INDICATIONS

There are many patients for whom a TOLAC is appropriate. Women who have undergone one previous low-transverse cesarean delivery typically should be offered a TOLAC. Evaluations of this cohort reveal a rate of uterine rupture of < 1% (0.7%–0.9%).3 While many women fall into this category, there are other women for whom a TOLAC may be an option, but their cases may require additional consideration. Women with more than one previous low-transverse hysterotomy are one such group. Rates of uterine rupture for those with multiple C-sections are slightly increased over the baseline rate, as noted previously; however, the absolute risk itself remains low. Table 52-1 presents the various types of incisions and ...

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