Socioeconomic disadvantage and racial/ethnic disparities in low-risk cesarean birth in California

Abstract

Our objective was to assess the relationship of socioeconomic disadvantage and race/ethnicity with low-risk cesarean birth. We examined birth certificates (2007-2018) linked with maternal hospitalization data from California; the outcome was cesarean birth among low-risk deliveries (ie, nulliparous, term, singleton, vertex [NTSV]). We used generalized estimation equation Poisson regression with an interaction term for race/ethnicity (n = 7 groups) and a measure of socioeconomic disadvantage (census tract-level neighborhood deprivation index, education, or insurance). Among 1 815 933 NTSV births, 26.6% were by cesarean section. When assessing the joint effect of race/ethnicity and socioeconomic disadvantage among low-risk births, risk of cesarean birth increased with socioeconomic disadvantage for most racial/ethnic groups, and disadvantaged Black individuals had the highest risks. For example, Black individuals with a high school education or less had a risk ratio of 1.49 (95% CI, 1.45-1.53) relative to White individuals with a college degree. The disparity in risk of cesarean birth between Black and White individuals was observed across all strata of socioeconomic disadvantage. Asian American and Hispanic individuals had higher risks than White individuals at lower socioeconomic disadvantage; this disparity was not observed at higher levels of disadvantage. Black individuals have a persistent, elevated risk of cesarean birth relative to White individuals, regardless of socioeconomic disadvantage.

Keywords: cesarean birth; health disparity; low-risk cesarean birth; race/ethnicity; socioeconomic disadvantage.

Figure 1

Cohort flow chart: California 2007-2018. ^a Exclusion for missing or improbable maternal age (<10 years, > 65 years or missing; n = 10), missing or improbable birth weight (<250 g or > 9000 g; n = 9), missing maternal education (n = 77 308), payer (n = 3885), and NDI (n = 27 927). BMI, body mass index; NDI, Neighborhood Deprivation Index; NTSV, nulliparous, term, singleton, vertex.

Figure 2

Risk ratios (RRs) representing the joint effects of socioeconomic disadvantage and race/ethnicity on risk of low-risk cesarean birth, using a single reference group: California, 2007-2018 (n = 1 815 933). The reference group for each chart is the least disadvantaged White population. Models include terms for age, prepregnancy body mass index, pregestational diabetes, pregestational hypertension, education, insurance, Neighborhood Deprivation Index (NDI), and race/ethnicity, as well as an interaction term for the given measure of socioeconomic disadvantage and race/ethnicity (n = 1 815 933). Higher NDI quartile corresponds to greater neighborhood disadvantage.

Figure 3

Risk ratios (RRs) representing the racial/ethnic disparity among low-risk cesarean births. Adjusted RRs are within strata of socioeconomic disadvantage, California, 2007-2018 (n = 1 815 933). The reference group for each chart is the White population for a given stratum. The models include maternal age, prepregnancy body mass index, pregestational diabetes, pregestational hypertension, education, insurance, Neighborhood Deprivation Index (NDI), and race/ethnicity, as well as an interaction term for the given measure of socioeconomic disadvantage and race/ethnicity (n = 1 815 933). Higher NDI quartile corresponds to greater neighborhood disadvantage.