The state of stress may be produced in the body by many causes, but the hypothalamopituitary-adrenal (HPA) axis plays a central coordinating role in the response to both internal and external stressors, substantially mediated through the release of corticotrophin-releasing hormone (CRH) and arginine-vasopressin (AVP). At every stage healthy development presumes the ready availability of a suitable mix of nutrients to support the current needs for cellular growth, elaboration, maturation, function and replication. Placental function plays a critical determining role in the process of fetal programming and the determination of the fetal phenotype. The changes in growth are associated with long-term alterations in behaviour, circulating levels of glucocorticoids and the set of the HPA axis in the offspring. Prepregnancy obesity is increasingly common, and despite the reality of obesity-related infertility assisted technologies enable more to become pregnant.