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Overview
The lower levels of estrogen in birth control pills suppress FSH and LH, "fooling" the pituitary gland into thinking a woman is pregnant. Ovulation will then not occur, which prevents pregnancy.
Review Date 1/10/2022
Updated by: John D. Jacobson, MD, Department of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.