Since the first oral contraceptive was approved by the FDA in 1960, hormonal birth control has given millions of women unprecedented control over their reproductive health and family planning decisions. This, in turn, has helped more American women enter the workforce over the past 50 years than ever before.
But while hormonal birth control is very effective at preventing pregnancies, scientists and physicians have long wondered why it’s not 100% effective in all women.
Are birth control failures always the result of user error, or could there be some other biological factor at play here? According to a group of researchers at the University of Colorado School of Medicine, a rare genetic variant could reduce the effectiveness of hormonal birth control in some women.
In a study recently published in the journal Obstetrics & Gynecology, the researchers describe an experiment in which they found that about 5 percent of women possess a genetic mutation which causes them to produce an enzyme that breaks down the hormones in birth control pills. As a result, these women may still be able to conceive even while taking birth control as directed.
“The biggest takeaway is that we’ve assumed for so long that if a woman taking birth control gets pregnant, then she must have done something wrong,” said ob-gyn and lead study author Aaron Lazorwitz in a recent interview. “Instead, maybe we need to pay more attention as physicians to other things that might be going on, like genetics, so we can give better, more individualized treatment to women…”
In the future, genetic testing could help physicians match their patients with forms of birth control that are best suited to their unique biology. Non-hormonal IUDs, for example, could be an ideal alternative for women whose genes make hormonal contraceptives more likely to fail.