Billings Clinic
Especially For:

Illness & Conditions - Definition

Menstrual Cycle

Menstrual Cycle

The menstrual cycle is the female body's monthly pattern of preparing for a possible pregnancy. The uterus grows a new lining called the endometrium; one of the ovaries releases an egg; and then, if the egg is not fertilized by sperm, the endometrium sheds from the uterus as a menstrual period.

  • Menstrual phase (period). The thickened lining of the uterus (endometrium) is shed, causing menstrual bleeding. Day 1 of the cycle is the first day of menstrual bleeding. Bleeding usually lasts for 4 to 6 days.
  • Follicular phase. The lining of the uterus thickens to prepare for pregnancy. Also, inside a sac (follicle) on the surface of an ovary, an egg becomes ready to be released.
  • Luteal phase. The egg is released (ovulation). Women's ovulation days can range from about day 7 to day 22 of the cycle. But for an individual woman, the ovulation day is usually quite consistent.
    • If the egg is fertilized by sperm, it may attach to (implant in) the lining of the uterus, and pregnancy begins.
    • If the egg is not fertilized or does not implant, the lining of the uterus is shed during the menstrual period, and the cycle starts again.

Current as of: March 12, 2014

Author: Healthwise Staff

Medical Review: Sarah Marshall, MD - Family Medicine & Femi Olatunbosun, MB, FRCSC - Obstetrics and Gynecology

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.

© 1995-2014 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.

Print This Page
Email to a Friend
Home | Contact | Site Map | Site Privacy Policy | Terms & Conditions | Patient Privacy Policy | Medical Records | Fast Command
2800 10th Ave. North | P.O. Box 37000 | Billings, Montana 59107 | 406.238.2500
© Copyright 2014 Billings Clinic. All Rights Reserved.