BACKGROUND From conception to 6 months of age, an infant is entirely dependent for its nutrition on the mother: via the placenta and then ideally via exclusive breastfeeding. This period of 15 months--about 500 days--is the most important and vulnerable in a child's life: it must be protected through policies supporting maternal nutrition and health. Those addressing nutritional status are discussed here. OBJECTIVE This paper aims to summarize research on policies and programs to protect women's nutrition in order to improve birth outcomes in low- and middle-income countries, based on studies of efficacy from the literature, and on effectiveness, globally and in selected countries involving in-depth data collection in communities in Ethiopia, India and Northern Nigeria. Results of this research have been published in the academic literature (more than 30 papers). The conclusions now need to be advocated to policy-makers. RESULTS The priority problems addressed are: intrauterine growth restriction (IUGR), women's anemia, thinness, and stunting. The priority interventions that need to be widely expanded for women before and during pregnancy, are: supplementation with iron-folic acid or multiple micronutrients; expanding coverage of iodine fortification of salt particularly to remote areas and the poorest populations; targeted provision of balanced protein energy supplements when significant resources are available; reducing teenage pregnancies; increasing interpregnancy intervals through family planning programs; and building on conditional cash transfer programs, both to provide resources and as a platform for public education. All these have known efficacy but are of inadequate coverage and resourcing. The next steps are to overcome barriers to wide implementation, without which targets for maternal and child health and nutrition (e.g. by WHO) are unlikely to be met, especially in the poorest countries. CONCLUSIONS This agenda requires policy decisions both at Ministry and donor levels, and throughout the administrative system. Evidence-based interventions are established as a basis for these decisions, there are clear advocacy messages, and there are no scientific reasons for delay.