Health Disparities
Sexual Orientation Disparities in Pregnancy Loss: Mediation by Chronic Hypertension Colleen A Reynolds* Colleen Reynolds Payal Chakraborty Isa Berzansky Brittany M. Charlton
Background: Emerging research suggests pregnancies among sexual minorities (e.g., heterosexual with same-sex experience, mostly heterosexual, bisexual, or lesbian individuals) are more likely to end in pregnancy loss (i.e., miscarriage or stillbirth) than among heterosexuals. Chronic hypertension is associated with increased risk of pregnancy loss, but no research has assessed whether hypertension mediates these disparities.
Methods: We pooled data from two cohorts, the Growing up Today Study and Nurses’ Health Study 3. Because of likely post-exposure confounding, we estimated interventional mediated effects (interventional pure natural direct effect [iPNDE] and total natural indirect effect [iTNIE]). Baseline confounders included demographics, and post-baseline confounders included marital status, socioeconomic status, health behaviors, chronic health conditions, and medically assisted reproduction.
Results: Among 14,178 pregnancies to completely heterosexual individuals (reference group), the prevalence of chronic hypertension was 6%, and 22% of pregnancies ended in a loss. Among 3,141 pregnancies to heterosexuals with same-sex experience/mostly heterosexuals, hypertension prevalence was 9%, and 25% ended in loss. Among 416 pregnancies to bisexuals/lesbians, hypertension prevalence was 8%, and 34% ended in loss. In complete case analyses, we found no evidence that chronic hypertension mediates disparities in pregnancy loss for heterosexuals with same-sex experience/mostly heterosexuals (iPNDE: 1.13; 95%CI: 0.93–1.37; iTNIE: 1.00; 95%CI: 0.98–1.03) or bisexuals/lesbians (iPNDE: 3.67; 95%CI: 2.14–5.73; iTNIE: 1.00; 95%CI: 0.93, 1.09). Multiple imputation and subgroup analyses are ongoing.
Conclusions: Future research must identify proximal pathways of pregnancy loss disparities to guide policy and clinical practice interventions among sexual minorities.