Menstrual Cycle

What is the Menstrual Cycle?

Every month after the first period, for the next 40 years a woman's body prepares itself for possible pregnancy. If she does not get pregnant, then a woman menstruates. Menstruation signals the beginning of a new monthly cycle of hormones in the reproductive system.


The pituitary gland releases gonadotropins (FSH and LH). The ovaries pick up the gonadotropins that cause the eggs in the ovaries to mature. The eggs, in their various phases of maturation in the ovary, release estrogen and progesterone. The pituitary releases more FSH and LH, depending on the levels of estrogen and progesterone in the blood. This feedback system responds to many environmental influences during reproductive years. For example, too much emotional or physical stress can cause irregular periods.

Changes to the Lining of the Uterus

Under the influence of estrogen, it gets thicker in the period before ovulation. After that, its glands begin to secrete nutrients.


The Menstrual Cycle is a natural part of life and shouldn't scare anyone.