Define Placental secretion of oestrogens During pregnancy?
Placental secretion of oestrogens increase with progression of pregnancy. Oestrogens perform many functions. They stimulate uterine growth, increase blood flow to the uterus and promote breast development. Oestrogens also induce prolactin secretion by the maternal pituitary. Prolactin secretion helps in mammary gland development. After delivery, oestrogen induced mammotrophs (prolactin secreting cells) in the pituitary secrete large amounts of prolactill to initiate and maintain milk production.
Another hormone that is increased in maternal plasma during pregnancy is cortisol. Cortisol enhances production of glucose from amino acids (gluconeogenesis) and also antagonizes the action of insulin. This way it increases the availability of glucose to the foetus which relies solely on glucose for its energy needs. In the marginally glucose intolerant women, these changes as a result of pregnancy may predispose them to frank impaired glucose intolerance.