Women who were using hormonal contraceptives when they met their partners remain more sexually attracted to them during pregnancy, according to a study published in the Annals of Sexual Behavior.

Hormone-based contraception includes many popular options such as birth control pills, patches, and injections. These contraceptives work by changing a woman’s hormone levels to mimic those found during pregnancy, which prevents ovulation. There is evidence that women using this type of contraceptive tend to find different traits attractive in potential mates than those who are not. In particular, women using hormonal contraception tend to prefer men with less masculine characteristics in terms of their behavior and facial appearance.

A team of researchers led by Kelly Cobey, of the University of Stirling, conducted a study designed to see whether the same differences in preferences were present during pregnancy. Their sample included 84 pregnant women recruited on the internet, all with husbands or long-term male relationship partners. Of those, 37 said they had been using hormonal contraception when they met their partners, while 47 said they had not. The researchers compared the two groups of women in terms of their reported levels of sexual desire for their relationship partners, and for men other than their partners.

The pregnant women who met their partners while using hormonal contraception reported feeling more sexually attracted to their partners than usual. Those who had not been using this type of contraceptive when they met their partners, on the other hand, reported feeling slightly less sexually attracted to them than usual. Women in both groups reported feeling considerably less sexual attraction than usual to men other than their partners.

These results seem to indicate that pregnancy may affect mate preferences in similar ways to hormonal contraceptive use. Pregnant women who had met their partners while having chemically altered hormone levels may have experienced renewed desire for the same traits that originally attracted them to their mates, in comparison to their pre-pregnancy state of unaltered hormone levels. Those experiencing these hormonal changes for the first time during pregnancy, however, may have felt somewhat less attracted to their partners due to changes in the traits they found most attractive.

“Our study is the first to examine sexual desire during pregnancy in relation to hormonal contraceptive use/non-use at the initiation of the relationship. As predicted, we found that women who met their partner while using hormonal contraception had significantly higher levels of sexual desire toward their partner during pregnancy,” the researchers wrote.

The study authors conclude that pregnancy and hormonal contraceptive use have similar effects on women’s preferences in partners. They suggest that this may have implications for relationship dynamics during pregnancy. Because pregnancy is often an important period of transition in a relationship, they suggest that understanding and anticipating these changes may be very valuable for couples’ well-being.