This is Your Period in 2 Minutes

Learn about the science and symptoms of a woman's 28-day menstrual cycle, hormones & period.

Explore the science behind the body's greatest mysteries -- in two minutes flat.
The length of the menstrual cycle varies from woman to woman, but the average is to have periods every 28 days. Regular cycles that are longer or shorter than this, from 23 to 35 days, are normal. The menstrual cycle is the time from the first day of a woman's period to the day before her next period.