Hormones of the Placenta: Estrogen,Progesterone & hCG. The placenta is anendocrine gland that is only present during pregnancy. In this lesson, you will learn about the hormones it produces, including human chorionic gonadotropin (hCG), progesterone,estrogen, and human placental lactogen (hPL).The main function of the placenta is to supply the baby with adequate nutrition. Blood from the mother goes through the placenta then into the umbilical cord attached, before reaching the baby. This blood contains oxygen, glucose and an array of other nutritional substances. Before the blood goes to the baby, the placenta works like a kidney to filter it of harmful substances, while also letting those that are good for the baby pass through.