Background: Maternal metabolism affects implantation, pregnancy, delivery, and long-term health of mother and child. Research question: What are the relevant aspects regarding congenital and acquired disorders of the metabolism that are important for a woman’s preconceptional and periconceptional health? Material and Methods: Reviews, meta-analyses, and recommendations published in the last 10 years on the topic of periconceptional metabolic health are presented. Results: Periconceptional health is now the focus of many basic research studies, especially in animal models or in the context of assisted reproduction. Regarding long-term effects of inborn errors of metabolism and acquired metabolic disorders, retrospective and increasingly prospective studies are available. Pathophysiological changes leading to increased long-term maternal and infant risks are presented. Conclusions: Preconception health has increasingly become a major part of preventive medicine. Not only negative pregnancy outcomes but also long-term adverse health effects for mother and child can be prevented by early detection and treatment of inborn errors of metabolism, as well as periconceptional optimization of weight, glucose metabolism, and thyroid function.