Which hormone is responsible for regulating the menstrual cycle?

The hormone responsible for regulating the menstrual cycle is progesterone. This hormone plays a crucial role in the menstrual cycle's latter half (the luteal phase) after ovulation has occurred. After an egg is released from the ovary, progesterone levels rise, which helps prepare the uterine lining for a potential implantation of a fertilized egg. If pregnancy does not occur, progesterone levels drop, leading to the shedding of the uterine lining, or menstruation.

Understanding the function of progesterone in the menstrual cycle highlights its importance not only in fertility but also in maintaining a woman's reproductive health. Other hormones such as estrogen also play critical roles in the menstrual cycle, but progesterone is specifically vital for the regulation that occurs after ovulation and prepares the body for possible pregnancy.