The most important time determining life-long health status of an individual is that spent developing in utero during pregnancy. To provide the optimal environment for development of her baby, the mother's body undergoes numerous changes. Apart from obvious adaptations in the uterus and breast, there are other equally important changes, particularly in the brain; appetite increases, hormone secretion is altered, and moods and behaviour change. These adaptations are driven by pregnancy hormones, and in particular, prolactin and placental lactogen (PL). If these changes do not occur properly, complications may occur, including gestational diabetes, preterm labour, and postpartum depression. Such adverse events can also have serious consequences on the baby, changing brain development and increasing life-long risk of many diseases, including obesity and mental illness. This Programme will evaluate how prolactin/PL helps the maternal brain adapt to pregnancy, and the consequences for the mother and baby when adaptive responses are compromised.