During the follicular phase of the
menstrual cycle, the lining of the uterus thickens to prepare for pregnancy. 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 (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 as blood
during the menstrual
period (below), and the cycle starts over.
ByHealthwise Staff Primary Medical ReviewerSarah Marshall, MD - Family Medicine Martin J. Gabica, MD - Family Medicine Specialist Medical ReviewerKirtly Jones, MD - Obstetrics and Gynecology
Sarah Marshall, MD - Family Medicine & Martin J. Gabica, MD - Family Medicine & Kirtly Jones, MD - Obstetrics and Gynecology
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.