Background: The Global Network for Women's and Children's Health Research (Global Network) supports and conducts clinical trials in resource-limited countries by pairing foreign and U.S. investigators, with the goal of evaluating low-cost, sustainable interventions to improve the health of women and children. Accurate reporting of births, stillbirths, neonatal deaths, maternal mortality, and measures of obstetric and neonatal care is critical to efforts to discover strategies for improving pregnancy outcomes in resource-limited settings. Because most of the sites in the Global Network have weak registration within their health care systems, the Global Network developed the Maternal Newborn Health Registry (MNHR), a prospective, population-based registry of pregnancies at the Global Network sites to provide precise data on health outcomes and measures of care. Methods: Pregnant women are enrolled in the MNHR if they reside in or receive healthcare in designated groups of communities within sites in the Global Network. For each woman, demographic, health characteristics and major outcomes of pregnancy are recorded. Data are recorded at enrollment, the time of delivery and at 42 days postpartum. Results: From 2010 through 2013 Global Network sites were located in Argentina, Guatemala, Belgaum and Nagpur, India, Pakistan, Kenya, and Zambia. During this period, 283,496 pregnant women were enrolled in the MNHR; this number represented 98.8% of all eligible women. Delivery data were collected for 98.8% of women and 42-day follow-up data for 98.4% of those enrolled. In this supplement, there are a series of manuscripts that use data gathered through the MNHR to report outcomes of these pregnancies. Conclusions: Developing public policy and improving public health in countries with poor perinatal outcomes is, in part, dependent upon understanding the outcome of every pregnancy. Because the worst pregnancy outcomes typically occur in countries with limited health registration systems and vital records, alternative registration systems may prove to be highly valuable in providing data. The MNHR, an international, multicenter, population-based registry, assesses pregnancy outcomes over time in support of efforts to develop improved perinatal healthcare in resource-limited areas. Study Registration: The Maternal Newborn Health Registry is registered at Clinicaltrials.gov (ID# NCT01073475).