PBLD5: Trial of Labor after Cesarean Delivery (TOLAC)

• In the appropriately selected candidate, a parturient can successfully avoid the risks and associated sequelae of a surgical delivery. These include a quicker recovery time, smaller blood loss, decreased risk of infection and thromboembolism, and the avoidance of surgical injury to surrounding organs (i.e. bladder, ureters, etc.).

• During a trial of labor after cesarean (TOLAC), there is always the chance of failure requiring emergent CD, and this can amplify the surgical risks mentioned above. Therefore, a careful risk/benefit analysis needs to be employed before selecting candidates for a TOLAC.

References:

1. Landon MB, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med. 2004; 351(25):2581-9.
2. Grobman W, et al. ACOG Practice bulletin no. 115: Vaginal birth after previous cesarean delivery. Obstet Gynecol. 2010; 116(2 Pt 1):450-63.

• Two prior CDs are not an absolute contraindication for attempting a TOLAC. According to some studies, the risk of rupture is less than 1% when a patient has had one or two prior low transverse uterine incisions. Of note, the risk can be as high as 10% with a history of prior classical cesarean section. 

• Various studies have shown either no significant increase, or marginal increased risk, between attempted TOLAC of a patient with two prior CDs as compared to one. It is for this reason that the American Congress of Obstetricians and Gynecologists (ACOG) has concluded that there is minimal difference in risk, and TOLAC is acceptable in both situations. Of note, there is not enough data to support TOLAC in a patient with three or more CDs. 

References:

1. Landon MB, et al. Risk of uterine rupture with a trial of labor in women with multiple and single prior cesarean delivery. Obstet Gynecol. 2006; 108(1):12-20.
2. Macones GA, et al. Obstetric outcomes in women with two prior cesarean deliveries: is vaginal birth after cesarean delivery a viable option? Am J Obstet Gynecol. 2005; 192:1223-8.

• Elective induction is inappropriate because the timing of TOLAC is too close to the last cesarean section.

• There has been a three-fold increase in uterine rupture associated with interdelivery intervals less than 18 months. Given that this patient has only an 11-month interdelivery period, strong reservations about proceeding with a TOLAC are appropriate.

Reference:

1. Stamilio DM, et al. Short interpregnancy interval: risk of uterine rupture and complications of vaginal birth after cesarean delivery. Obstet Gynecol. 2007; 110(5):1075.

• There are pharmaceutical and mechanical methods to induce labor. Pharmaceuticals are either prostaglandin-based medications such as misoprostol (Cytotec) and dinoprostone (Cervidil), or oxytocin, a synthetic hormonal analogue. Mechanical means include placement of a cervical foley balloon or laminaria. 

• When inducing a parturient for a TOLAC, the use of prostaglandins is contraindicated due to an unacceptably high risk of uterine rupture. In one study, there was a uterine rupture rate of 0.77% vs. 2.24% in patients being induced with non-prostaglandins vs. prostaglandins respectively. Therefore, the obstetrician in this case should reconsider the induction method.

Reference:

1. Grobman W, et al. ACOG Practice bulletin no. 115: Vaginal birth after previous cesarean delivery. Obstet Gynecol. 2010; 116(2 Pt 1):450-63.

• Parenteral opioids are a reasonable option for parturients in labor. However, some pitfalls of their application should be noted and mentioned when counseling patients. There have been only modest reductions noted on maternal pain scores and variable response noted with their use.

• It is a joint recommendation of the American Society of Anesthesiologists (ASA) and the Society for Obstetric Anesthesia and Perinatology (SOAP) to offer neuraxial anesthesia to parturients attempting a TOLAC and to do so early in labor.

• It should be noted that 60-80% of TOLACs are successful. However, parturients attempting a TOLAC have an overall higher risk of a repeat CD, and potentially an emergent one. Having a well-functioning labor epidural in place allows for a safe and expeditious transition to CD anesthesia if indicated.

References:

1. Plante L, et al. ACOG Practice bulletin no. 177: Obstetric Analgesia and Anesthesia. Obstet Gynecol. 2017; 129(4):e73-e89.
2. Apfelbaum JL, et al. Practice Guidelines for Obstetric Anesthesia: An Updated Report by the American Society of Anesthesiologists Task Force on Obstetric Anesthesia and the Society for Obstetric Anesthesia and Perinatology. Anesthesiology. 2016; 124(2):270-300.

• There are many etiologies for decelerations. The clinical scenario needs to be evaluated and a differential diagnosis created. The appropriate etiology should then be addressed in order to correct the disturbance. Of note, early decelerations are not pathologic and their presence is part of a normal labor process.

• In contrast to labor pain, uterine rupture is often associated with constant unrelenting pain that is not associated with contractions.

• There is a concern that dense labor epidural analgesia could diminish the pain associated with uterine rupture. For that reason, some advocate the use of a dilute epidural concentration for infusion and boluses.

• Uterine rupture is typically associated with a poor fetal heart rate tracing, which would be unaffected by epidural analgesia. In parturients undergoing a TOLAC, close attention to the fetal heart rate tracing is essential to diagnosing uterine rupture. Changes in the fetal heart tracing are cited as the most common sign, occurring in 70% of uterine ruptures. Other less reliable signs may be fetal bradycardia, increased uterine contractions, increased vaginal bleeding, and loss of fetal station.

References:

• 1. Macone G, et al. ACOG Practice bulletin no. 116: Management of intrapartum fetal heart rate tracings. Obstet Gynecol. 2010; 116(5):1232-40.
  2. Toppenberg KS, et al. Uterine rupture: what family physicians need to know. Am Fam Physician. 2002; 66(5):823-8.

• 1:300 parturients will present as an unanticipated difficult intubation. This is an 8 fold greater incidence than the general population. This fact is a major contributing factor to the routine use of neuraxial anesthesia for parturients.

• Although not the preferred anesthetic during pregnancy, general endotracheal anesthesia (GETA) is sometimes necessary. GETA has been associated with difficult intubation, aspiration, maternal awareness, uterine relaxation and fetal sedation. During emergencies, such as uterine rupture or a category 3 fetal heart rate tracing, expedient delivery with a rapid-onset, reliable anesthetic is mandatory.

• If GETA becomes necessary, a rapid sequence induction should be performed while maintaining cricoid pressure. The goal is to quickly secure the airway while minimizing the risk of aspiration. A combination of succinylcholine and propofol is often used for induction, though each case should be weighed with its own risk benefit analysis.

References:

1. Chestnut, David H. Chestnut’s Obstetric Anesthesia: Principles and Practice. Elsevier Saunders, 2014.
2. Mhyre JM, et al. The unanticipated difficult intubation in obstetrics. Anesth Analg. 2011; 112(3):648-52.

• Absolutely not! If a patient is attempting a TOLAC, there must be resources and personnel available for an emergent repeat CD and possible maternal hemorrhage. This would include direct access to an operating room (OR), obstetrician, anesthesiologist, nursing, and other OR personnel. 

• An operating room should be readily available with equipment, blood products, and medications to allow for resuscitation of a hemorrhaging parturient. Additionally, protocols should be in place that allow for the expeditious acquisition of blood products, i.e. a massive transfusion protocol.

• These requirements can be discouraging for patients desiring a TOLAC in a small hospital with lacking resources. In this situation, conversation between the patient and provider is encouraged in order to discuss risk, benefits, and alternatives. 

• Of note, ACOG maintains that emergency cesarean sections should be performed within 30 minutes from “decision to incision.” 

References:

1. Grobman W, et al. ACOG Practice bulletin no. 115: Vaginal birth after previous cesarean delivery. Obstet Gynecol. 2010; 116(2 Pt 1):450-63.
2. Kilpatrick, Sarah J. Guidelines for Perinatal Care. American Academy of Pediatrics and American College of Obstetrics and Gynecology, 2017.