Can Birth Control Change the Partner You Choose?

Your doctor filled you in on potential physical side effects of your birth control. But could the Pill be messing with your mind, too? (Corbis Images) 

After I got married, my gynecologist suggested I try birth control — and I promptly refused, giving him only one reason: “Research has shown that birth control may change the partner you choose.” (Blame my background as a sex editor!) My reply was met with a confused stare — after all, my husband was seated just inches from the exam table, so I’d clearly successfully chosen a mate. But I was adamant: I didn’t want to take a drug that could affect my mind in so drastic a way.

Though befuddled, my doctor respected my decision, and my husband simply added the anecdote to his repertoire of funny stories. I, however, continued to hold onto my belief that birth control might have effects extending beyond the body and into the mind.

New research suggests my claim wasn’t so crazy. Choosing a partner while on the Pill may affect a woman’s marital satisfaction down the road, according to a 2014 study in the Proceedings of the National Academy of Sciences. When the researchers followed 118 newlywed couples for four years, they found that women who went off of hormonal birth control after getting hitched experienced a drop in relationship happiness — but only if their husband wasn’t a particularly attractive guy.

Related: What to Expect When You Go On or Off the Pill

“We had trained coders rate the faces of each of these spouses on a scale of 1 to 10,” says study co-author Andrea Meltzer, an assistant professor of psychology at Southern Methodist University. As subjective as that may sound, “people tend to agree on who’s attractive and who’s not,” she says.

So what’s typically considered appealing? Think Ken dolls or contestants on The Bachelorette: highly masculine, symmetrical faces — the types of features research has found women favor during their fertile period. “The fluctuation in hormones probably makes them more attuned to features that are perceived as attractive, such as high testosterone, symmetry, and a defined jaw,” explains Meltzer.

And it’s not just because masculine-looking guys are nice to look at: “From an evolutionary standpoint, these features signal to women that these men have greater genetic fitness, which means they have better genes to pass on to children,” explains lead study author Michelle Russell. In other words, when women are capable of getting pregnant, they may subconsciously flock to partners who’d make healthier babies.

By contrast, during non-fertile times in their cycle, women tend to prefer men who offer material benefits. This suggests that from a purely adaptive standpoint — think cavewomen protecting their young — women are wired to mate with the manly men, but then to marry the stable providers.

Now add the Pill to the equation. “When women take hormonal contraceptives, their hormone profile mimics that of a pregnant woman,” says Meltzer. As a result, they don’t experience the normal hormonal ups and downs of the menstrual cycle, and because they never ovulate, they miss out on the fertile phase, the time when women favor highly masculine men. “Because of this flatlining of normal cyclic changes in hormone levels, your [mate] preferences don’t go through the cyclic changes,” says Lisa Welling, an assistant professor of psychology at Oakland University, who studies the effects of birth control on mate choice.

The result: Women on hormonal contraceptives may land in long-term partner-seeking mode — and never leave. “They tend to be attracted to comparably more feminine men,” says Welling, who was not involved in the study. In a 2008 study in Evolution and Human Behavior, for example, women on the Pill were less drawn to masculine-looking men than women not taking hormonal contraceptives.

When taking the Pill, “women are more attuned to what would be considered a good dad — qualities that make them stable, and more likely to stay in a relationship,” says Meltzer. Or, as Welling puts it, “it seems there’s a bit of a trade-off, whether you want the slightly more feminine, but invested, kind, good father, versus the more masculine, good genes, sexy individual.”

Is choosing a less sexy — but ultimately stable — guy really such a bad thing, since commitment is desirable in a long-term partner? (And, of course, in modern times, many of us have children with and marry the same person.)

It may simply be a balancing act — that is, finding a partner who falls somewhere in the middle, since “attractiveness really does influence relationship outcomes,” Meltzer says. As her new study showed, once former birth control users with less attractive husbands began experiencing the normal hormonal fluctuations of the menstrual cycle — including the fertile time when masculinity becomes attractive — their spouse’s lacking looks began to detract from the relationship.

However, Meltzer notes, the women who chose a partner while on birth control were not, as a rule, married to less attractive dudes — her study simply showed that the ones who did pick less handsome mates experienced a decline in satisfaction after quitting their contraceptives. “So it’s not necessarily that [women on birth control] are choosing less attractive partners,” she says. “But their partner’s attractiveness is affecting their satisfaction once they come off of hormonal contraception.”

In fact, research shows that changes in preferences mainly affect short-term partner choices, although, of course, one-night-stands can turn into long-term relationships.

Related: IUDs: Is This Kind of Birth Control Right for You?

Translation: Taking the Pill may not drive you to marry a guy with bad genes — but changing your birth control status after walking down the aisle could alter your feelings toward the partner you picked. “Change in hormonal contraceptive use after the relationship is formed, but not contraceptive use per se, seems to predict the woman’s sexual satisfaction with her partner,” explains Welling. “In other words, discontinuing or initiating birth control while involved with a partner may suddenly change a woman’s preferences, which may affect things like sexual satisfaction.”

Likewise, if you marry a guy you had a one-night stand with, then start taking birth control, your partner preferences may shift toward the “good dad” type — and away from the super-hunk type you initially chose.

So should women who are playing the field be worried about taking the Pill? Welling doesn’t think so — “more research is definitely needed” — although she does suggest considering a “trial period,” where you discontinue use of hormonal contraceptives when a relationship is starting to get serious, rather than waiting to do so after getting married. (Of course, this is a decision you should discuss with your partner and your doctor.)

“Access to birth control is incredibly important, but I also think it’s incredibly important to have a full understanding of all potential side effects,” Welling says. “The research does seem to suggest that initiating or discontinuing hormonal contraceptives has an impact on your behavior toward your partner.”

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