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Did You Know Your Weight Can Affect "The Pill"?

A study featured in the May 2002 issue of the medical journal Obstetrics and Gynecology found that overweight women stand a higher chance of accidentally getting pregnant while using "the pill."

Under normal circumstances, if birth control pills are taken as prescribed, only about 1 in 1,000 women become accidentally pregnant.* The recent research reflected in the study showed that women who weigh more than 155 pounds are 60% more likely to have their oral contraceptive fail... even if they are taking it as prescribed. The risk is highest for overweight women utilizing low-dose or very-low-dose birth control pills.

For their study, the researchers examined pregnancy rates among women aged 18-39 who use oral contraception. The findings suggest that a possible explanation for the pill's failure to prevent pregnancy in some overweight women is due to a change in metabolic rate (caused by a higher body weight) which leads to the alteration of a hormone level that is necessary for contraception.

In light of these findings, the study's authors advise that physicians should take women's weight into account when suggesting oral contraceptives as a sole form of birth control.

  • Source:
  • Obstetrics and Gynecology, May 2002
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