Your birth control pill could affect your relationship, and not just because it halts baby-making. A new study published in the Proceedings of the National Academy of Science followed 118 couples who met while the woman was on hormonal birth control and found that going off the pill could impact how attracted she was to her partner.
Whether a woman's attraction to her mate shifted post-Pill seemed to be determined by how objectively good-looking he was by evolutionary standards, which means his attractiveness is an indicator of genetic fitness. Some women with partners who were not conventionally attractive reported being less attracted to him after stopping oral contraceptives, whereas a decrease was not seen in women whose partners were conventionally handsome.
"Women who choose a partner when they’re on hormonal contraceptives and then stop taking them will prioritize their husband's attractiveness more than they would if they were still on it," says Michelle Russell, the Florida State graduate student who is the lead author on the study. "The effect that it would have on her marital satisfaction would carry more weight.” That means that if your husband is not conventionally attractive and you go off the Pill, his attractiveness might bother you more than before. Conversely, if you're bored of your foxy husband, going off the Pill might make you more excited about him. Maybe.
Russell says the change may be attributed fluctuating estrogen levels, but says there could be many hormonal reasons for this effect. She also doesn't suggest that this finding should dissuade women from using oral contraceptives. "This is just one finding," she says.
Other studies have looked at how the Pill affects female attraction. A 2008 paper published in The Proceedings of the Royal Society B found that while women are usually attracted to the scent of men who are genetically different from them, women on the Pill are attracted to the scent of men who are more genetically similar. This may be because the Pill fools your body into thinking it's pregnant, and pregnancy can affect attraction. In discussing the 2008 study, Scientific American hypothesized that while non-pregnant women would be more attracted to genetically dissimilar men (to avoid the possibility of incest and maximize immunity of their offspring,) women on the Pill may be more drawn to genetically similar men because pregnant women seek out family members.
Another study of 365 couples published this year in Psychological Science found that women who went on or off the Pill during a relationship were less sexually satisfied than women who were consistently on the Pill or who had never been on it.
While the exact mechanisms for how oral contraceptives affect female attraction aren't totally clear, there is mounting evidence that hormonal birth control can affect more than just fertility. But scientists are not necessarily advocating that the risks outweigh the benefits. "Any drug that you take, people want to be informed consumers," Russell says. "This is just one factor women might want to consider when deciding whether or not to use them."