3) Placental Estrogen
during the first month of gestation the corpus luteum secretes estrogen in response to hCG stimulation, after that the estrogen will be secreted from placenta by the effect of hCG and its level increase until delivery reaching several hundred times higher than during ovarian cycle.
a) Estrogen stimulate uterine enlargement which is important to the growing fetus.
b) It stimulate breast growth (duct and nipples) in pregnant women.
c) It stimulates enlargement of external genitalia and relaxation of the pelvic ligaments which help the passage of the fetus through the birth canal in delivery.
4) Placental human chorionic somatomammotropin (hCS)
It is secreted at about 5 weeks of gestation and it is play a role in the metabolism and nutrition of both mother and fetus.