Menstrual Cycle

Menstrual cycle: Lining of uterus thickens and egg is released
Menstrual cycle: Uterine lining is shed

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: November 27, 2023

Author: Healthwise Staff
Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

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. Learn how we develop our content.