Maternal Undernutrition before and during Pregnancy and Offspring Health and Development.

Maternal undernutrition remains a critical public health problem. There are large regional and within-country disparities in the burden of underweight, anemia, and micronutrient deficiencies across the globe. Driving these disparities are complex and multifactorial causes, including access to health services, water and sanitation, women's status, and food insecurity as well as the underlying social, economic, and political context. Women's health, nutrition, and wellbeing across the continuum of preconception to pregnancy are critical for ensuring positive pregnancy and long-term outcomes for both the mother and child. In this review, we summarize the evidence base for nutrition interventions before and during pregnancy that will help guide programs targeted towards women's nutrition. Growing evidence from preconception nutrition trials demonstrates an impact on offspring size at birth. Preconception anemia and low preconception weight are associated with an increased risk of low birth weight and small for gestational age births. During pregnancy, several evidence-based strategies exist, including balanced-energy protein supplements, multiple micronutrient supplements, and small-quantity lipid nutrient supplements for improving birth outcomes. There, however, remain several important priority areas and research gaps for improving women's nutrition before and during pregnancy. Further progress is needed to prioritize preconception nutrition and access to health and family planning resources. Additional research is required to understand the long-term effects of preconception and pregnancy interventions particularly on offspring development. Furthermore, while there is a strong evidence base for maternal nutrition interventions, the next frontier requires a greater focus on implementation science and equity to decrease global maternal undernutrition disparities.