Contributions of the nurses' health studies to reproductive health research

Objectives.To review the Nurses' Health Study's (NHS's) contribution to identifying risk factors and long- Term health consequences of reproductive events. Methods.We performed a narrative review of the NHS I, NHS II, NHS3, and Growing Up Today Study (GUTS) publications between 1976 and 2016. Results. Collection of detailed reproductive history to identify breast cancer risk factors allowed the NHS to document an association between menstrual irregularities, a proxy for polycystic ovary syndrome (PCOS), and increased risk of diabetes and cardiovascular disease. The NHS II found that infertility associated with ovulation problems and gestational diabetes are largely preventable through diet and lifestyle modification. It also identified developmental and nutritional risk factors for pregnancy loss, endometriosis, and uterine leiomyomata. As women in NHS II age, it has become possible to address questions regarding long- Term health consequences of pregnancy complications and benign gynecologic conditions on chronic disease risk. Furthermore, the NHS3 and GUTS are allowing new lines of research into human fertility, PCOS, and transgenerational effects of environmental exposures. Conclusions. The multigenerational resources of the NHSs and GUTS, including linkages of related individuals across cohorts, can improve women's health from preconception through late adulthood and onto the next generation.