What is the primary hormone that maintains pregnancy?

The primary hormone that maintains pregnancy is progesterone. This hormone plays a crucial role in creating and maintaining the appropriate environment for a developing fetus.

Progesterone is produced mainly by the corpus luteum in the early stages of pregnancy, and later it is also produced by the placenta. Its functions include preparing the uterine lining for a potential implantation of an embryo and sustaining that lining throughout gestation. Additionally, progesterone helps to suppress uterine contractions, which is vital for preventing premature labor, allowing for the embryo to grow and develop safely.

While estrogen, oxytocin, and human chorionic gonadotropin (hCG) also have important roles in pregnancy, they do not primarily maintain the pregnancy. Estrogen contributes to uterine growth and supports fetal development, while hCG helps to maintain the corpus luteum in early pregnancy, signaling the body to keep producing progesterone. Oxytocin is more associated with labor and delivery, facilitating uterine contractions during childbirth, rather than maintaining a pregnancy.