Final answer:
Progesterone is a vital female hormone secreted by the ovaries and later by the placenta, crucial for maintaining the uterine lining for implantation and preventing premature labor by inhibiting uterine contractions.
Step-by-step explanation:
The progesterone hormone plays a crucial role in the female body, particularly in maintaining a pregnancy. It is secreted mainly by the ovaries and is responsible for various functions, such as maintaining the uterine lining for potential implantation of a fertilized egg and supporting the production of cervical mucus that aids in the survival and transport of sperm. During pregnancy, the corpus luteum and later the placenta produce important hormones, including estrogen, progesterone, and human chorionic gonadotropin (hCG).
Progesterone works in concert with estrogen to promote changes in the endometrium during the menstrual cycle and to prepare the uterus for receiving an embryo. The hormone inhibits the development of new ovarian follicles and suppresses uterine contraction to prevent premature birth. As pregnancy progresses, progesterone levels decrease, which allows for the uterine contractions to increase, leading up to childbirth. Progesterone, along with other hormones, also contributes to the maturation and maintenance of reproductive organs and the appearance of secondary sex characteristics in females at puberty.