Use of calculators and models for predicting vaginal birth after a previous cesarean delivery
- Torri D Metz, MD
Torri D Metz, MD
- Assistant Professor
- Maternal-Fetal Medicine
- University of Colorado Denver
After a first cesarean delivery, a pregnant woman has to choose between an elective repeat cesarean delivery (ERCD) and a trial of labor after cesarean (TOLAC) with the goal of achieving a vaginal birth (VBAC). In order to make this decision, both clinicians and patients typically desire individualized information about (1) the chance of VBAC and (2) the balance between the risks of maternal or fetal morbidity with TOLAC compared with ERCD.
This information is also important on a population level, especially in the setting of a rising cesarean delivery rate, as selection of candidates who are most likely to deliver vaginally after a previous cesarean can minimize the costs of ERCD and failed TOLAC. The cost-effectiveness of TOLAC is dependent on the likelihood of VBAC. In a decision analytic model with a hypothetical cohort of 100,000 women undergoing TOLAC versus ERCD, TOLAC was cost-effective when the likelihood of VBAC was >47.2 percent . In another study, if all women who were calculated to be good candidates for VBAC underwent TOLAC, the cesarean rate would have been reduced from 70.4 to 25.5 percent (assuming a VBAC rate of 70 percent) .
This topic will discuss the use of calculators for counseling women about TOLAC. All other issues related to TOLAC are reviewed separately. (See "Choosing the route of delivery after cesarean birth".)
The goal of TOLAC calculators and models is to predict a woman's chance of VBAC based on her demographic and clinical risk factors [3-8]. The chance of VBAC is not only important as a direct measure of outcome but also as an indirect measure of maternal morbidity: Major maternal morbidity is lowest in women who have VBAC (morbidity 0.2 percent), higher in women who undergo ERCD (morbidity 0.8 percent), and highest in women who have a repeat cesarean delivery after a failed TOLAC (morbidity 3.8 percent) .
Although a TOLAC calculator or model can predict the probability of vaginal birth, which is a key concern of women contemplating TOLAC versus ERCD, a variety of other factors also influence a woman's decision regarding route of delivery. These factors are not addressed by calculators and are discussed in detail elsewhere. (See "Choosing the route of delivery after cesarean birth", section on 'Shared decision-making'.)
- Gilbert SA, Grobman WA, Landon MB, et al. Lifetime cost-effectiveness of trial of labor after cesarean in the United States. Value Health 2013; 16:953.
- Metz TD, Stoddard GJ, Henry E, et al. How do good candidates for trial of labor after cesarean (TOLAC) who undergo elective repeat cesarean differ from those who choose TOLAC? Am J Obstet Gynecol 2013; 208:458.e1.
- Metz TD, Stoddard GJ, Henry E, et al. Simple, validated vaginal birth after cesarean delivery prediction model for use at the time of admission. Obstet Gynecol 2013; 122:571.
- Troyer LR, Parisi VM. Obstetric parameters affecting success in a trial of labor: designation of a scoring system. Am J Obstet Gynecol 1992; 167:1099.
- Flamm BL, Geiger AM. Vaginal birth after cesarean delivery: an admission scoring system. Obstet Gynecol 1997; 90:907.
- Weinstein D, Benshushan A, Tanos V, et al. Predictive score for vaginal birth after cesarean section. Am J Obstet Gynecol 1996; 174:192.
- Grobman WA, Lai Y, Landon MB, et al. Development of a nomogram for prediction of vaginal birth after cesarean delivery. Obstet Gynecol 2007; 109:806.
- Grobman WA, Lai Y, Landon MB, et al. Does information available at admission for delivery improve prediction of vaginal birth after cesarean? Am J Perinatol 2009; 26:693.
- McMahon MJ, Luther ER, Bowes WA Jr, Olshan AF. Comparison of a trial of labor with an elective second cesarean section. N Engl J Med 1996; 335:689.
- Eden KB, McDonagh M, Denman MA, et al. New insights on vaginal birth after cesarean: can it be predicted? Obstet Gynecol 2010; 116:967.
- Macones GA, Cahill AG, Stamilio DM, et al. Can uterine rupture in patients attempting vaginal birth after cesarean delivery be predicted? Am J Obstet Gynecol 2006; 195:1148.
- Macones GA. Clinical outcomes in VBAC attempts: what to say to patients? Am J Obstet Gynecol 2008; 199:1.
- https://mfmu.bsc.gwu.edu/ (Accessed on May 22, 2014).
- Metz TD, Allshouse AA, Faucett AM, Grobman WA. Validation of a vaginal birth after cesarean delivery prediction model in women with two prior cesarean deliveries. Obstet Gynecol 2015; 125:948.
- Costantine MM, Fox K, Byers BD, et al. Validation of the prediction model for success of vaginal birth after cesarean delivery. Obstet Gynecol 2009; 114:1029.
- Yokoi A, Ishikawa K, Miyazaki K, et al. Validation of the prediction model for success of vaginal birth after cesarean delivery in Japanese women. Int J Med Sci 2012; 9:488.
- Chaillet N, Bujold E, Dubé E, Grobman WA. Validation of a prediction model for vaginal birth after caesarean. J Obstet Gynaecol Can 2013; 35:119.
- Annessi E, Del Giovane C, Magnani L, et al. A modified prediction model for VBAC, in a European population. J Matern Fetal Neonatal Med 2016; 29:435.
- Costantine MM, Fox KA, Pacheco LD, et al. Does information available at delivery improve the accuracy of predicting vaginal birth after cesarean? Validation of the published models in an independent patient cohort. Am J Perinatol 2011; 28:293.
- Abdel Aziz A, Abd Rabbo A, Sayed Ahmed WA, et al. Validation of the close-to-delivery prediction model for vaginal birth after cesarean delivery in a Middle Eastern cohort. Int J Gynaecol Obstet 2016; 134:75.
- Schoorel EN, Vankan E, Scheepers HC, et al. Involving women in personalised decision-making on mode of delivery after caesarean section: the development and pilot testing of a patient decision aid. BJOG 2014; 121:202.
- Schoorel EN, van Kuijk SM, Melman S, et al. Vaginal birth after a caesarean section: the development of a Western European population-based prediction model for deliveries at term. BJOG 2014; 121:194.
- Smith GC, White IR, Pell JP, Dobbie R. Predicting cesarean section and uterine rupture among women attempting vaginal birth after prior cesarean section. PLoS Med 2005; 2:e252.
- Mardy AH, Ananth CV, Grobman WA, Gyamfi-Bannerman C. A prediction model of vaginal birth after cesarean in the preterm period. Am J Obstet Gynecol 2016; 215:513.e1.
- Grobman WA, Lai Y, Landon MB, et al. Can a prediction model for vaginal birth after cesarean also predict the probability of morbidity related to a trial of labor? Am J Obstet Gynecol 2009; 200:56.e1.
- Chaillet N, Bujold E, Dubé E, Grobman WA. Validation of a prediction model for predicting the probability of morbidity related to a trial of labour in Quebec. J Obstet Gynaecol Can 2012; 34:820.
- RISK FACTORS PREDICTIVE OF TOLAC SUCCESS AND FAILURE
- MFMU Network calculator for use at entry to prenatal care
- MFMU Network calculator for use at admission for delivery
- SELECTED PREDICTION MODELS
- Shared decision-making model
- VBAC score at admission for delivery model
- Smith model
- Model for preterm pregnancies
- OUR APPROACH
- SUMMARY AND RECOMMENDATIONS