Contraceptive pills may reduce a woman's bone density

Tuesday, January 26, 2010


Longer use of the pill seems to lessen bone density.

THE QUESTION Do oral contraceptives affect the bone density of the young women who most often take them?

THIS STUDY involved 606 girls and women, 14 to 30 years old; 389 of them were taking birth control pills. Teens in the study had been taking the pill for an average of nine months and women for 18 months, and about a third were taking oral contraceptives that contained a low estrogen dosage. Bone density measurements did not vary between teens who had been taking the pill and those who had not. However, among women 19 to 30 years old, bone density declined as length of contraceptive use grew. Density was lowest among women who had taken oral contraceptives for more than two years and who were taking a pill with a low estrogen dosage.

WHO MAY BE AFFECTED? Girls and women who take oral contraceptives. An estimated 19 percent of U.S. women 15 to 44 years old take birth control pills. Among young women, the pill is the most commonly used form of birth control. One component of oral contraceptives, estrogen, has been shown to preserve bone density.

CAVEATS Data on contraceptive use were based on the participants' recollection. Other factors not accounted for could have affected the participants' bone density. They were paid $30 for the bone density testing.

FIND THIS STUDY January issue of Contraception.

LEARN MORE ABOUT birth control at http://www.nichd.nih.gov/health and http://www.acog.org.

-- Linda Searing

The research described in Quick Study comes from credible, peer-reviewed journals. Nonetheless, conclusive evidence about a treatment's effectiveness is rarely found in a single study. Anyone considering changing or beginning treatment of any kind should consult with a physician.

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