ABSTRACT
Physiological changes in every organ system enable the mother to provide for the nutritional and metabolic demands of the foetus and the newborn and to meet the physiological stresses of labour. Progressive anatomical, physiological and biochemical alterations occur throughout pregnancy and the post-partum period. The physiological changes in the mother are caused by or associated with changes in the endocrine system. The placenta acts as an endocrine organ as it produces both peptide (human chorionic gonadotrophin [HCG] and human placental lactogen [HPL]) and steroid hormones. Throughout pregnancy, the placenta synthesizes progesterone and oestrogen from precursors derived from the foetal adrenal cortex. The pituitary gland increases the secretion of prolactin, adrenocorticotrophin and melanocyte-stimulating hormone. The production of growth hormone is reduced, possibly by HPL. Placental steroids reduce pituitary gonadotrophin production, whereas adrenal hormone production is increased.
