One Carbon Metabolism and Mammalian Pregnancy Outcomes.

Nutrition during pregnancy plays a crucial role in pregnancy health and outcomes. One-carbon metabolism is involved in a variety of physiological processes in mammals, including nucleic acid synthesis, amino acid homeostasis (methionine, serine and glycine), epigenetic regulation, redox balance and neurodevelopment. Among the nutrients involved in one-carbon metabolism, only folate has been extensively studied for its effect on pregnancy. We reviewed the current evidence linking nutrients with one-carbon units during pregnancy to the development of oocytes, embryos and placentas as well as maternal and offspring health. We describe the sources of mammalian one-carbon units, the pathways active in mammalian one-carbon metabolism, the maternal and fetal needs for one-carbon units and their functions during pregnancy. The demand for one-carbon metabolism is highest during pregnancy, from the perspective of the entire lifetime of a mammal. The primary types of one-carbon metabolism in mammals are the folate cycle, methionine cycle and transsulfuration pathway, and the metabolites in one-carbon metabolism are linked to one another. The primary type of one-carbon metabolism varies at different pregnancy stages, which largely depends on the developmental characteristics and requirements for each stage of pregnancy (for example, the methylation programming of the embryo, neural development of the fetus, fetal growth and placenta development). Therefore, we call for an overall consideration of one-carbon metabolism requirements for different pregnancy stages, specifically, the balance of all the nutrients involved, not just one single nutrient in one-carbon metabolism. Moreover, we suggest the establishment of an ideal one-carbon metabolism requirement model according to the requirements for the different pregnancy stages to support optimal pregnancy outcomes and maternal and offspring health. This article is protected by copyright. All rights reserved.