This article discusses the impacts of midlife social exposures on health in later life, especially for women. Of particular interest is the period of early adulthood. Social epidemiology and life course frameworks help reveal how workplace exposures, family dynamics, and public policies related to work and family shape opportunities in midlife that have long-run health consequences. This is especially important for American women, who have experienced health disadvantages over the last decades compared to women in similarly advanced industrialized countries. In most countries, single women are especially at high risk for poor health at older ages, and job strain can elevate future risks particularly for this subpopulation. Public policies such as maternity leave can reduce risks for poor mental health outcomes among working mothers 30 to 40 years after childbirth, suggesting that the period of early and middle adulthood may influence health trajectories well into old age.