Why does your period come early?

Updated February 21, 2017

Your period can occur early (less than 28 days from the beginning of your last period) due to an increase in cortisol. Cortisol is a substance that is released in the brain in response to stress. Cortisol can cause an imbalance in hormones such as oestrogen and progesterone, which regulate your periods. Emotional stress, physical fatigue, substance abuse and eating disorders can cause higher levels of cortisone to be produced. A healthy lifestyle that includes exercise, proper nutrition and time for relaxation and play can reduce your stress level dramatically.

Onset of Menstruation

Menarche is the term used for the onset of menstruation. Most girls experience this between the ages of 10 and 16. Many girls will have early periods, late periods or spotting between periods. This is due to changing hormone levels triggered by the pituitary gland during puberty. Most girls have irregular periods for about three years before the body's hormones stabilise.


Menopause is another period of life in which hormone levels undergo dramatic transition. This disturbance can cause early or late periods before the stage in which menstruation ceases entirely. The average age for menopause is 51, and the length of this process varies from person to person. Periods often are irregular for several years before disappearing.

Birth Control

Birth control pills work by altering the body's hormones. Sometimes missing pills and getting off track in your monthly dosage schedule can trigger an early period. Some women experience early periods when they first begin taking the pills as their bodies are adjusting to the hormones in the birth control.

Health Conditions

Some health conditions can cause early or late periods. These conditions include ovarian cysts, inflammatory bowel disease and endometriosis. If your periods are irregular for several months in a row or if you have an irregular period accompanied by other symptoms such as severe pain or bleeding, visit your physician as soon as possible.

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About the Author

Charlotte Johnson is a musician, teacher and writer with a master's degree in education. She has contributed to a variety of websites, specializing in health, education, the arts, home and garden, animals and parenting.