Which hormone is directly linked to the early stages of pregnancy maintenance?

Progesterone is the hormone that plays a crucial role in maintaining the early stages of pregnancy. After fertilization, the corpus luteum, which forms from the collapsed ovarian follicle post-ovulation, produces progesterone. This hormone is essential for preparing the uterine lining for implantation and helps maintain the endometrium, which is vital for the embryo's development.

During the early stages of pregnancy, progesterone prevents uterine contractions that could lead to rejection of the embryo and inhibits the immune response to create a supportive environment for the developing fetus. Additionally, it supports the ongoing production of important nutrients and maintains a healthy pregnancy until the placenta takes over its role later on.

While luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are involved in ovarian function and the menstrual cycle, they do not directly support the maintenance of pregnancy after conception. Estrogen also plays a role in pregnancy but works alongside progesterone rather than being the primary hormone responsible for its maintenance in the early stages.