During the follicular phase of the menstrual cycle, the lining of the uterus thickens. An egg becomes ready to be released inside a sac (follicle) on the surface of an ovary. During the luteal phase, the egg is released (ovulation). If the egg is fertilized by sperm, it may attach to the lining of the uterus (implant), and pregnancy begins. If the egg is not fertilized or a fertilized egg doesn't implant, the lining of the uterus is shed as blood during the menstrual period (below), and the cycle starts over.
Current as of: August 2, 2022
Author: Healthwise Staff Medical Review: Sarah Marshall MD - Family Medicine Martin J. Gabica MD - Family Medicine Kathleen Romito MD - Family Medicine Rebecca Sue Uranga MD - Obstetrics and Gynecology JoLynn Montgomery PA - Family Medicine
Medical Review:Sarah Marshall MD - Family Medicine & Martin J. Gabica MD - Family Medicine & Kathleen Romito MD - Family Medicine & Rebecca Sue Uranga MD - Obstetrics and Gynecology & JoLynn Montgomery PA - Family Medicine
Medical Review:Sarah Marshall MD - Family Medicine & Martin J. Gabica MD - Family Medicine & Kathleen Romito MD - Family Medicine & Rebecca Sue Uranga MD - Obstetrics and Gynecology & JoLynn Montgomery PA - Family Medicine
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 and Privacy Policy. Learn how we develop our content.
The Health Encyclopedia contains general health information. Not all treatments or services described are covered benefits for Kaiser Permanente members or offered as services by Kaiser Permanente. For a list of covered benefits, please refer to your Evidence of Coverage or Summary Plan Description. For recommended treatments, please consult with your health care provider.