There is increasing evidence of a link between metabolic and mental health during the peripartum period. Gestational diabetes mellitus (GDM), the most common metabolic disorder in pregnant women, is a risk factor for the development of peripartum depression and anxiety symptoms, and conversely, increased symptoms of these mental health problems are a risk factor for GDM. Both conditions are independently and even more so in combination associated with an increased risk of adverse outcomes for both mother and child. However, the biological mechanisms underlying the relationship between peripartum mental and metabolic health are poorly understood. Therefore, the LinkMe project aims to contribute to a better understanding of the overlapping and discriminative biological correlates of peripartum mental and metabolic health by performing untargeted metabolomic analyses, assessing candidate gene polymorphism and evaluating blood serotonin parameters. Through untargeted metabolomic analyses of plasma samples from pregnant women, we aim to identify metabolites and metabolic pathways associated with both GDM as well as with symptoms of peripartum depression and anxiety in women with normal glucose tolerance and GDM. Through complementary untargeted metabolomic analyses of cord plasma samples, we aim to identify metabolic pathways that are influenced by maternal metabolic and mental health, advancing thus our understanding of the developmental origins of health and disease. In parallel, we will perform expression analyses of selected genes in relevant metabolic tissues that regulate maternal physiology during pregnancy, i. e. in the placenta and adipose tissue. The analyses of genetic polymorphisms will focus on serotonin pathway genes and candidates from the available literature. The proposed studies will improve our understanding of the biological basis of peripartum metabolic and mental health and may have implications for clinical practice in the future.