PROJECT SUMMARY/ABSTRACT Compared to heterosexual women, sexual minority women (i.e., those with same-sex attractions, same-sex behavior, and/or a lesbian/gay/bisexual identity) are vulnerable to poor gynecological health; for ex- ample, they are more likely to experience sexual assault and to encounter barriers to care. Yet, despite the mounting evidence of these gynecological disparities, little is known about the extent to which obstetrical and perinatal health differ across sexual orientation groups. This gap is especially troubling since sexual minorities have more risk factors (e.g., depression, substance use, obesity) for adverse obstetrical and perinatal out- comes compared to heterosexuals. Few data are available to adequately quantify sexual orientation-related obstetrical and perinatal health disparities, but preliminary results from small, cross-sectional datasets reveal striking disparities: sexual minority women experience twice the number of pregnancies ending in miscarriage and stillbirth and twice the number of children born extremely preterm and low birthweight compared to hetero- sexual women. Quantifying such disparities necessitates the use of large, longitudinal datasets to better inform interventions. This project's objective is to address the knowledge gaps in sexual orientation-related obstetrical and perinatal health by collecting and analyzing national data from three unique, longitudinal, intergenerational cohorts. The Nurses' Health Study 2 (NHS2) began in 1989 when our research group enrolled female nurses aged 25–42 years (now 56–73 years). In 1996 and 2004, our research group enrolled NHS2 offspring aged 9– 16 years (now 25–39 years) into the Growing Up Today Study (GUTS). These cohorts comprise almost 150,000 participants with nearly as many pregnancies, including >30,000 pregnancies among sexual minori- ties. The proposed project will leverage existing data—including nuanced sexual orientation data—to identify new pregnancies among GUTS participants during the height of their reproductive years and collect data about a third generation: the offspring of GUTS participants. Combining these new and existing data will enable us to fill critical gaps, for example by detailing outcomes across different generations and sexual orientation sub- groups (e.g., bisexuals, lesbians). This study will quantify the obstetrical health of sexual minority and hetero- sexual women as well as the perinatal health of children born to sexual minority and heterosexual women. Drawing on the Minority Stress Model, the study will also identify mediators and moderators of sexual orienta- tion-related differences in obstetrical and perinatal health. By collecting detailed, longitudinal data across three generations with data on obstetrical/perinatal outcomes as well as mediators and moderators, the proposed research is a substantive, innovative departure from the status quo. This project will produce the first thorough evaluation of obstetrical and perinatal health of a neglected population—sexual minority women and their off- spring—and will have a positive impact by revealing the needs of these vulnerable groups, informing targeted interventions and improving the health of subsequent generations.

PROJECT NARRATIVE The proposed research is relevant to public health because one in five women in the U.S. is a sexual minority and, of the nearly 4 million births in U.S. each year, an estimated 800,000 children are born to sexual minority women. Sexual minority women and their children appear to be one of the most vulnerable maternal and child health populations, yet almost no research has documented their needs. Revealing the needs of at- risk groups—a major priority area for the NIH—will inform interventions to reduce entrenched disparities and dramatically improve obstetrical and perinatal health.