E6 Decoding the VBAC Calculator: Science, Bias, and Decision Making

The VBAC Facts® Podcast

This episode with VBAC Facts® Founder Jen Kamel dives into the accuracy and impact of VBAC calculators. Jen discusses a variety of factors influencing predicted VBAC odds as well as actual VBAC rates, including race, BMI, reason for prior cesarean, bias, provider preference, and VBAC bans. Key research, such as Harris 2019, Nguyen 2020, and most recently Ledbetter 2024, reveal that VBAC calculators often underpredict VBAC odds. Hear lived experiences from readers and the challenges they face with the application of these calculators. Learn more about the strengths and limitations of VBAC calculators and their impact on informed decision-making in birthing choices. Access additional resources and training at VBACfacts.com.

• 00:22 Introduction to VBAC Calculators
• 02:30 Study Questions VBAC Accuracy: Harris 2019
• 05:47 The Role of a Prior Failure to Progress (FTP) Cesarean
• 07:31 ACOG's Labor Arrest/ FTP Definitions
• 09:48 On Calibrating VBAC Calculators Before Use
• 11:19 Impact of Race & Racism on VBAC Odds
• 14:59 Readers Share Their VBAC Calculator Experiences
• 19:27 BMI, Bias, and VBAC Calculators
• 21:20 Limitations and Misuse of VBAC Calculators
• 26:13 VBAC Calculator Latinx Accuracy: Nguyen 2020
• 27:36 VBAC Calculator Hispanic BMI Accuracy: Ledbetter 2024
• 33:50 BMI & the VBAC Calculator: A Reader's Story
• 39:17 Relevant Factors the VBAC Calculator Doesn't Consider
• 40:53 ACOG: Recruit me for the VBAC Practice Bulletin Committee
• 42:27 Questions to Ask Yourself Before You Use the VBAC Calculator
• 43:06 Final Thoughts and Resources

Mentioned on the show

• Read the companion article, see the first three VBAC calculators, and download the handout for this episode.
• Birth Monopoly's How to File A Complaint for Mistreatment in Maternity Care.
• The Maternal-Fetal Medicine Network VBAC calculator.
• "In an effort to reduce the number of primary cesareans, ACOG released new labor arrest definitions in 2014." American College of Obstetricians & Gynecologists and the Society for Maternal-Fetal Medicine. (2014). Safe prevention of the primary cesarean delivery. Obstetric Care Consensus No. 1. Obstetrics & Gynecology, 123, 693-711.
• Collins, J. W., David, R. J., Handler, A., et al. (2004). Very low birthweight in African American infants: The role of maternal exposure to interpersonal racial discrimination. American Journal of Public Health, 94(12), 2132-2138.
• Harris, B. S., Heine, P. H., Park, J., Faurot, K., Hopkins, M., Rivara, A., . . . Jelovsek, E. (2019). Are prediction models for vaginal birth after cesarean accurate? American Journal of Obstetrics & Gynecology, 220, 492.e1-7.
• Ledbetter, A., Wandtke Herrmann, T., Lupa, K., & Graupe, M. (2024). Observed Versus Predicted Vaginal Birth After Cesarean for Patients of a Community Health Center. Journal of Midwifery & Women's Health.
• Metz, T. D., Stoddard, G. J., Henry, E., et al. (2013). How do good candidates for trial of labor after cesarean (TOLAC) who undergo elective repeat cesarean differ from those who choose TOLAC? American Journal of Obstetrics & Gynecology, 208(6), 458.e1-6.
• Nguyen, M. T., Hayes-Bautista, T. M., Hsu, P., Bragg, C., Chopin, I., & Shaw, K. J. (2020). Applying a Prediction Model for Vaginal Birth after Cesarean to a Latina Inner-City Population. American Journal of Perinatology Reports, 10(02), e148-e154.
• "One study reported that half of those who had a cesarean for FTP after labor induction were not even 6 centimeters." Zhang, J., Troendle, J., Reddy, U.,et al. (2010). Contemporary cesarean delivery practice in the United States. The American Journal of Obstetrics & Gynecology, 203(4), 326.e1-326.e10.
• The Truth About VBAC™ for Families
• The Truth About VBAC™ for Professionals
• VBAC Facts® Professional Membership
• VBAC Facts® Speaking: Schedule an in-person training in your community
• VBAC Facts® Consulting: Schedule a consulting call with Jen

Have a comment or question for the podcast? Want to suggest a guest we should interview or a topic we should discuss? Go to https://vbacfacts.com/podcast to give us your feedback!

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