Variation in Vaginal Birth After Cesarean by Maternal Race and Detailed Ethnicity.

Objective Our objective was to examine the likelihood of vaginal birth after cesarean (VBAC) for women in Massachusetts. Methods We used birth certificate data among term, singleton, vertex presentation births by repeat cesarean or VBAC to conduct logistic regression models to examine the likelihood of VBAC for women categorized into standard classifications of race and ethnicity and into 31 detailed ethnicities. Data were analyzed for the entire study period (1996-2010, N = 119,752) and for the last 5 years (2006-2010, N = 46,081). Results The adjusted odds of VBAC were lowest for non-Hispanic Black mothers (0.91, CI [0.85, 0.98]) and highest for Asian/Pacific Islander mothers (1.41, CI [1.31, 1.53]) relative to non-Hispanic White women. VBAC rates ranged from 5.8 % among Brazilians to 29.3 % among Cambodians. The adjusted odds of VBAC were lower for 7 of the 30 ethnic groups (range of AORs 0.40-0.89) and higher for 8 of the 30 ethnic groups (range of AORs 1.18-2.11) relative to self-identified American mothers. For the last 5 years, Asian/Pacific Islander mothers had a higher adjusted VBAC rate (1.39, CI [1.21, 1.60]), as did 9 of the 30 ethnic groups (range of 1.25-1.84). Only Brazilian mothers had lower rates (0.37, CI [0.27, 0.50]), relative to self-identified American mothers. Conclusions Detailed maternal ethnicity explains the variation in VBAC rates more precisely than broad race/ethnicity categories. Improvements in our public health data infrastructure to capture detailed ethnicity are recommended to identify and address disparities and improve the quality of maternity care.