Assessing Racial/Ethnic Variation and Trends in Vaginal Birth after Cesarean in California: A Retrospective Cohort Study Using Linked Birth Certificate and Hospital Discharge Records

Objective Increasing the vaginal birth after cesarean (VBAC) rate to 18% was a Healthy People 2020 goal. Detailed data on racial/ethnic differences in VBAC rates is lacking and can inform efforts to equitably increase VBAC rates. This study aimed to assess racial/ethnic variation in VBAC rates and to describe group trends in VBAC rates in California between 2011 and 2021. Study Design This retrospective cohort study used a database of birth certificates linked to hospital discharge records. We analyzed singleton, term live births among people who had a history of at least one prior cesarean birth, no identified contraindications to a vaginal birth, and self-identified their racial/ethnic group as Hispanic or non-Hispanic (American Indian-Alaskan Native (AIAN), Asian, Black, Hawaiian/Pacific Islander, or white). VBAC births were identified from birth certificate records. Differences between VBAC rates were assessed using univariable and multivariable Poisson log-linear regression while adjusting for potential confounders. Results A total of 607,808 birthing people were included (2,234 AIAN, 84,899 Asian, 34,217 Black, 2,559 Hawaiian/Pacific Islander, 334,116 Hispanic, 149,783 white). Over the study period, Hawaiian/Pacific Islander birthing people had the highest average VBAC rate at 11.5% (AIAN, 6.5%; Asian, 8.8%; Black, 8.0%; Hispanic, 7.4%; white, 9.5%). In adjusted models, Black (aRR = 1.06, 95% CI: 1.01-1.11) and Hawaiian/Pacific Islander (aRR = 1.43, 95% CI: 1.27-1.61) birthing people were more likely to have a VBAC compared with white birthing people, while Hispanic birthing people were less likely (aRR = 0.96, 95% CI: 0.93-0.98). VBAC rates increased significantly (p < 0.001) over time for all groups except AIAN birthing people. Conclusion VBAC rates increased for most racial/ethnic groups in California. With the exception of the Hawaiian/Pacific Islander group, there were small and likely not clinically significant differences in the chances for a VBAC across groups. No group in California met the Healthy People 2020 goal VBAC rate of 18%. Key Points VBAC rates increased for most racial/ethnic groups. The VBAC rate for AIAN birthing people did not increase. No group met the Healthy People 2020 goal VBAC rate of 18%.