ABSTRACT
This chapter presents a brief account of the endocrine events implicated in parturition and lactation. It deals with the endocrine events that play an important role in the onset and course of labour. The chapter examines the major hormones of pregnancy and know in which tissues they are synthesised and what their major actions. Progesterone levels in the maternal blood stream rise steeply during pregnancy. Lactation is milk secretion from the breasts, which become enlarged during pregnancy through the action of several hormones, including: cortisol, estrogens, growth hormone, Human placental lactogen, prolactin, and progesterone. The chapter outlines the central events of the suckling reflex. The suckling reflex is the reflex letting down of milk, caused by the mechanical stimulation of the nipple. Mechanical stimulation of the nipple sends afferent nerve impulses up the spinal cord to the supraoptic and paraventricular nuclei of the hypothalamus.
