Although many hormone levels are affected in the body when a woman becomes pregnant, the following are the most common hormones and their functions:
hCG (human chorionic gonadotropin This is the one that causes the nausea often associated with pregnancy, and is produced only during pregnancy.
Progesterone It is released by the ovaries and the placenta. It stimulates the thickening of the endometrial lining to prepare for embryo implantation.
Estrogen It is produced by the placenta and helps maintain a healthy pregnancy.
hPL (human placental lactogen) Produced by the placenta, provides nutrition to the fetus and stimulates milk glands in the breasts.