What is the function of progesterone in the female reproductive system?

The function of progesterone in the female reproductive system primarily involves preparing the uterus for pregnancy. After ovulation, when the ovaries release an egg, progesterone is produced by the corpus luteum. This hormone plays a crucial role in thickening and maintaining the uterine lining, creating a suitable environment for a fertilized egg to implant. If pregnancy occurs, progesterone supports the growth and development of the embryo by maintaining the uterine lining throughout the first trimester and preventing further ovulation during that time.

While other hormones, such as luteinizing hormone, are responsible for stimulating ovulation and regulating menstrual cycles, and while prolactin is the hormone that initiates lactation, progesterone's primary role in preparing the uterus for a potential pregnancy is essential in the reproductive process. This foundational role makes it a vital hormone in the context of conception and the menstrual cycle.