If an egg is fertilized and implants in the uterine wall, pregnancy occurs; if pregnancy does not occur, estrogen and progesterone levels drop, causing the uterine lining to shed during the period.

Authors

• Person: Not available Organization: Cleveland Clinic
  Menstrual Cycle (Normal Menstruation): Overview & Phases

Sources

• Menstrual Cycle (Normal Menstruation): Overview & Phases my.clevelandclinic.org Cleveland Clinic via serper

Referenced by nodes (6)

• estrogen concept
• progesterone concept
• ovum concept
• endometrial lining concept
• period concept
• pregnancy concept