Human Chorionic Gonadotropin (hCG) is a hormone secreted by the placenta, playing a crucial role in sustaining pregnancy by supporting the corpus luteum and progesterone production during the early stages.
Relaxin is produced later in pregnancy to help relax the pelvic muscles in preparation for delivery.
Oxytocin triggers uterine contractions during labor.
Human Placental Lactogen aids in fetal growth and metabolism, though it doesn't directly contribute to maintaining pregnancy.