Disparities in primary Cesarean birth by sexual orientation: a population-based analysis across three longitudinal...

The study aim was to quantify differences in risk for Cesarean birth vary by sexual orientation.

We pooled data from singleton, live births in the Nurses' Health Studies 2 and 3, and the Growing Up Today Study (N = 102,298 pregnancies). We used generalized estimating equations to fit logistic models for risks of primary Cesarean birth comparing sexual minority (SM) to completely heterosexual participants, controlling for year and age. SM participants were further stratified into heterosexual with prior same-sex experience (i.e., identifying as heterosexual, but with same-sex attractions, behaviors, or prior SM identity), mostly heterosexual, bisexual, and lesbian/gay subgroups. We examined heterogeneity by parity, labor induction, and racialized identity.

SM participants had higher risks of primary Cesarean birth than their completely heterosexual peers (adjusted odds ratio [OR] = 1.07, 95% confidence interval [CI] 1.01-1.12), with increases most pronounced among pregnancies to heterosexual participants with prior same-sex experience (OR = 1.12, 95% CI 1.04-1.20). Labor induction was associated with a higher magnitude disparity (OR for induced labor = 1.21, 95% CI 1.09-1.35; OR for spontaneous labor = 0.91, 95% CI 0.83-1.01; p-value for interaction = 0.09). Racialized identity or parity did not moderate sexual orientation-related disparities in primary Cesarean birth.

SM people have increased risks for primary Cesarean birth, but these vary across sexual orientation subgroups. We found increased risks for a rarely studied subgroup of sexual minority people, those who identify as heterosexual but have prior same-sex experience. These disparities are most pronounced when labor is induced. All participants were assumed to be women based on surveys querying sex and birth histories, but we were limited in generalizability due to not knowing their gender identities.

National Institutes of Health (United States).