Birth control pill - series

Release of estrogen

Release of estrogen

During a normal menstrual cycle, hormones stimulate the ovary causing an egg to ripen. The uterine lining thickens preparing itself for implantation of a fertilized egg and the cervical mucus thins to help sperm reach the egg.

Update Date: 3/30/2010

Updated by: Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Redmond, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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