Hormones secreted by the placenta are Estrogen, Progesterone, hCS, hPL & hCG. The placenta is an endocrine gland that is only present during pregnancy. hCG or the human chorionic gonadotrophin is secreted in excess amount in early pregnancy. Its presence in urine is used for the pregnancy test. hCS or human placental somato mammotropin is also called placental lactogen. It acts a mild growth hormone.