Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality in women, yet early-life reproductive health factors are often overlooked as critical markers of future cardiovascular risk. This chapter explores the relationship between reproductive milestones—such as menarche timing, menstrual cycle irregularities, polycystic ovary syndrome (PCOS), and endometriosis—with long-term cardiometabolic health. Epidemiological evidence suggests that early or late menarche, irregular menstrual cycles, and PCOS are associated with enhanced risks of hypertension, type 2 diabetes, dyslipidemia, and atherosclerotic cardiovascular disease. Additionally, endometriosis, an estrogen-dependent inflammatory disorder, has been linked to endothelial dysfunction and an elevated risk of ischemic heart disease and stroke. Infertility, often indicative of underlying hormonal and metabolic imbalances, has been associated with a higher incidence of heart failure, particularly heart failure with preserved ejection fraction. The growing recognition of these reproductive markers as early predictors of CVD underscores the need for a more integrated, lifespan-based approach to cardiovascular risk assessment and prevention in women. As such, the menstrual cycle can be considered a “vital sign” for cardiometabolic health in reproductive age women. Clinicians should routinely incorporate reproductive history into cardiovascular evaluations, ensuring early identification of at-risk individuals. Preventive strategies, including lifestyle modifications, pharmacologic interventions, and multidisciplinary care models, are essential to mitigating cardiovascular risk and improving long-term health outcomes in women. By recognizing the reproductive origins of cardiovascular risk, we can shift toward a more proactive approach in preventing CVD in young and middle-aged women.