Birth control pill
| Normal female anatomy |
|
The internal female reproductive organs include the uterus,
ovaries, cervix, and vagina. These organs are necessary to produce
a successful pregnancy. To prevent pregnancy, birth control pills
affect how these organs function.
|
| FSH and LH from pituitary gland |
|
Follicle stimulating hormone (FSH) and luteinizing hormone (LH)
stimulate the ovary into producing a ripe egg ready for
fertilization by sperm during a normal ovulation cycle.
|
| 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.
|
| Release of LH |
|
Estrogen in the body causes the pituitary gland to release LH,
stimulating the ovary to produce a ripe egg.
|
| Birth control pill |
|
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, therefore preventing
pregnancy.
|
| Progestin in pill |
|
The progesterone in birth control pills creates a thick cervical
mucus, making it difficult for sperm to reach the uterus. It also
impedes an egg from attaching itself to the uterine lining
(endometrium) because of changes in the cellular structure of the
lining.
|
Review Date: 12/31/2008
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine,
Division of General Medicine, Department of Medicine, University of
Washington School of Medicine; and 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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