The Menstrual Cycle

Each month, a master gland in a woman’s brain sends out a series of hormones (natural chemicals) to start, balance, and coordinate her entire reproductive system.  These hormones stimulate the ovaries to release one of the 40,000-400,000 eggs, which have been present since birth-far more than will be needed during childbearing years.  Hormones also thicken and prepare the lining of the uterus (endometrium) for the potential implantation of an embryo.

After ovulation, the egg travels through the fallopian tube where it may be fertilized if sperm are present.  Fertilization triggers additional hormones, which tell the uterus to maintain its ready state.  If fertilization does not occur, the blood-filled lining of the uterus will naturally die off and pass out of the body in menstruation.  This discharge of blood through the vagina continues for an average of three to seven days.

This cycle is typically repeated once a month.  It varies from woman to woman, with an average cycle length of 21 to 35 days, depending on her body and various other influences.