Describe the hormonal interaction in the human female from conception to birth

After fertilization, the fertilized egg becomes implanted in the uterine wall and pregnancy results.

The cells of the forming placenta produce the hormone, human chorionic gonadotrophin (HCG) which preserve the corpus luteum. Corpus luteum continues to secrete progesterone which, together with a small steady secretion of oestrogen from the ovary, maintains the continued development of the uterus and prevents miscarriages.

Progesterone and oestrogen also inhibit the anterior pituitary so that it stops producing FSH. This prevents any further follicles from developing during pregnancy.

After the first three or four months of pregnancy, the corpus luteum begins to disintegrate and the placenta takes over the job secreting progesterone and oestrogen.

Progesterone and oestrogen stimulate the increase in the size of the breast during pregnancy due to development of mammary glands.

Oestrogen makes the uterine walls more sensitive to the effects of oxytocin. Oxytocin causes the smooth muscles of the uterus to contract

Progesterone and oestrogen inhibit the secretion of prolactin and therefore formation of milk.

The decrease in progesterone after birth allows prolactin to stimulate the alveoli to secrete milk