Picking a partner while on the Pill might have lasting ramifications on marital satisfaction, new research finds.

The new findings show that women who start or stop hormonal contraception during a relationship tend to experience a drop in sexual satisfaction, according to the new study, published today (Nov. 17) in the journal Proceedings of the National Academy of Sciences.

But even odder, women in the study who got together with their future husbands while taking hormonal birth control and who later stop using the medication also become less satisfied with their marriages — but only if their husbands were less attractive than average. If hubby was a hottie, women became more satisfied after stopping the hormones, the study showed.

"Given that women [tend to] prioritize attractiveness differently when they are on versus off [hormonal contraceptives], I thought that going on or off [hormonal contraceptives] should affect how happy they are with their partner," said study leader Michelle Russell, a graduate student in psychology at Florida State University. [7 Surprising Facts About the Pill]

The effect may occur because the progesterone and estrogen in hormonal birth control affect women's fertility, and thus what they are looking for in a mate, according to the study. Previous studies have found that women prefer more masculine-looking partners when they are ovulating. The theory, which is still controversial, is that masculine men have good genes, which would benefit a woman's offspring if she were to get pregnant.

Satisfaction and the pill

Russell said she and her colleagues wanted to better understand how a woman's husband's attractiveness may interplay with her birth control to affect satisfaction.

Indeed, they found that birth control did play a role in their satisfaction with their partner. When married women were asked about sexual satisfaction, those who were using the same birth control regimen as when they began the relationship reported higher levels than those who had changed their regimen. For example, women who began dating their husbands while on the pill who were still on the pill during their marriage were more sexually satisfied, on average, than women who were on the pill when the couple started dating, but who quit after the honeymoon.

Overall marital satisfaction was a bit more complicated, Russell told Live Science. Women in the study who began their relationships while on hormonal birth control became less satisfied with the marriage after stopping the medicine, but only if her husband was less attractive than average. In contrast, the women on hormonal birth control who married men who were more attractive than average were actually more satisfied in their marriages after stopping the hormones.

That finding suggests that women who are having natural menstrual cycles are more intrigued by good looks, and thus get a satisfaction boost after stopping the pill if their husband is good-looking, Russell said. In contrast, a woman who married a less-attractive man and who then stopped the pill might become generally more interested in handsome faces, only to find herself disappointed by her husband's, Russell added.

Long-term study

The study followed 48 couples for four years of marriage, and another 70 couples for one year. The researchers asked the couples about their birth-control use and their marital and sexual satisfaction, and also asked uninvolved judges to rate the attractiveness of the husbands' faces based on photographs.

The long-term nature of the study strengthens the researchers' confidence in the findings, Russell said, but she warned that the study's design makes it difficult to prove that the hormones caused the satisfaction changes. However, the researchers were able to rule out some other external factors that may influence relationship satisfaction, she said.

"In particular, we were able to control for several other factors that might affect wives' marital satisfaction, such as whether or not she was pregnant, whether or not she was trying to get pregnant and her husband's marital satisfaction," Russell said.

One quirk of the findings was that, although stopping hormonal birth control affected satisfaction, starting it mid-relationship did not. This was surprising, Russell said, and more research should look at the reason for this.

The researchers also want to break down future studies by brand of birth control.

"Previous research suggests that estrogen partially accounts for women’s preferences for specific qualities in their partners, and [hormonal contraceptives] vary in the amount of estrogen they contain," Russell said. "It's possible that the effects we found may be stronger or weaker depending on the amount of estrogen in a particular formulation."

Hormonal contraception is very popular in the United States. According to the Guttmacher Institute, 17 percent of all women ages 15 to 44 were on the birth control pill as of 2010. Another 5 percent or so used hormone injections, a hormonal patch or a vaginal ring as birth control.

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