background: Most reproductive failures originate during the periconceptional period and are influenced by the age and the lifestyle of parents-to-be.We advance the hypothesis that these failures can arise as a partial consequence of derangements to one-carbon (1-C) metabolism (i.e. metabolic pathways that utilize substrates/cofactors such as methionine, vitamin B12, folate). 1-C metabolic pathways drive the synthesis of proteins, biogenic amines and lipids required for early growth, together with the synthesis and methylation ofDNA and histones essential for the regulation of gene expression.We review how deficiencies in periconceptional 1-C metabolism affect fertility and development together with underlying mechanisms derived from animal studies. methods: A literature search was performed using PubMed and bibliographies of all relevant original research articles and reviews. results:We define 'periconception' as a 5-6-month period in women embracing oocyte growth, fertilization, conceptus formation and development toWeek 10 of gestation (coinciding with the closure of the secondary palate in the embryo). During this period significant epigenetic modifications to chromatin occur that correspond with normal development. Subtle variations in 1-C metabolism genes and deficiencies in 1-C substrates/cofactors together with poor lifestyle, such as smoking and alcohol consumption, disturb 1-C metabolism and contribute to subfertility and early miscarriage and compromise offspring health. Procedures used in assisted reproduction can also disturb these metabolic pathways and contribute to poor pregnancy outcomes. conclusions: Evidence presented indicates that parental nutrition and other lifestyle factors during the periconceptional period can affect reproductive performance via 1-C metabolic pathways. This knowledge provides opportunities for treatment and prevention of reproductive failures and future non-communicable diseases.

B vitamins, Epigenetics, Fertility, Folate, Preconception care,
Human Reproduction Update
Department of Gynaecology & Obstetrics

Steegers-Theunissen, R.P.M, Twigt, J.M, Pestinger, V, & Sinclair, K.D. (2013). The periconceptional period, reproduction and long-term health of offspring: The importance of one-carbon metabolism. Human Reproduction Update, 19(6), 640–655. doi:10.1093/humupd/dmt041