by Juliana French & Andrea Meltzer
140 million. That’s how many women world-wide are estimated to use hormonal contraceptives such as The Pill. The main function of hormonal contraceptives (and a leading reason for why so many women use them) is to decrease the likelihood of conception. But through administering synthetic hormones to achieve protection against unwanted pregnancy, hormonal contraceptives incidentally alter a myriad of other physiological and psychological processes. In a recent paper, we examined the extent to which hormonal contraceptives may alter processes important for maintaining satisfying relationships, such as sexual satisfaction.
Sex is a central feature of adult romantic relationships, which is reasonable considering the adaptive value sex has for reproductive success. It is therefore not surprising that frequent and satisfying sex plays an important role in the maintenance of people’s long-term romantic relationships. Nevertheless, one of the most common side effects of hormonal contraceptives—an evolutionarily novel medical advancement—is decreased sexual desire among women who use them.
Hormonal contraceptives are therefore, by definition, an evolutionary mismatch. A classic, easy-to-digest example of an evolutionary mismatch concerns modern food availability. Humans have an evolved tendency to seek highly caloric foods because this would have been adaptive in our evolutionary history when such foods were scarce. In 2020, however, this evolved tendency may lead you to crave chocolate chip cookies and fast food. When not kept in check, these (once adaptive) cravings contribute to modern rates of obesity. Similar to the abundance of highly caloric foods in our modern environment being mismatched to our evolved psychology, hormonal contraceptives may be mismatched to our evolved relationship processes, explaining, at least in part, some relationship dysfunction such as sexual dissatisfaction.
So, now you may be wondering, “although hormonal contraceptives help to prevent unwanted pregnancy, are they harmful for my relationship?”
Not so fast – there’s more to the story.
A recent study suggests that whether a woman uses a hormonal contraceptive may be less important for her relationship than whether she changes her hormonal contraceptive use after relationship formation. Imagine one woman, for example, who was not using a hormonal contraceptive when she met her partner but decides to start using The Pill after they have been together for a little while (perhaps because she is likely to engage in relatively more frequent sex and doesn’t want to become pregnant). Imagine another woman who was using The Pill when she met her partner but decides to discontinue using hormonal birth control at some point in her relationship (perhaps because she and her partner are trying to become pregnant).
Hormonal contraceptive use that differs from a woman’s use when she met her partner is called hormonal contraceptive incongruency. Notably, many women become hormonal contraceptive incongruent at some point during their ongoing, long-term relationships. Moreover, because many women begin and discontinue hormonal contraceptives multiple times in the course of a relationship, they repeatedly fluctuate between being congruent and incongruent. Are women less sexually satisfied during those times when their hormonal contraceptive use is incongruent (compared to congruent) from their use at relationship formation? This is exactly the question we sought we answer.
We tested whether such within-person changes in hormonal contraceptive use that results in incongruency is associated with decreases in sexual satisfaction. To do this, we asked 203 heterosexual, newlywed wives if they were using a hormonal contraceptive when they began dating their husbands. Then, at the start of their marriages and again every four to six months for up to four years, those wives (a) completed a measure of sexual satisfaction and (b) reported whether they were currently using a hormonal contraceptive. Results demonstrated that wives reported lower sexual satisfaction at times when their hormonal contraceptive use was incongruent with their use at relationship formation compared to times when their hormonal contractive use was congruent with their use at relationship formation.
“Wives reported lower sexual satisfaction at times when their hormonal contraceptive use was incongruent with their use at relationship formation”
There are two ways to be incongruent with respect to hormonal contraceptive use, however. Whereas some women do not use hormonal contraceptives when they meet their partners and become incongruent when they begin using them, other women use hormonal contraceptives when they meet their partners and become incongruent when they discontinue their use. Is one form of incongruency more strongly tied to decreases in sexual satisfaction than the other? The short answer is, no. In our data, changes in sexual satisfaction that were associated with incongruency did not differ for wives who were incongruent by “starting” hormonal contraceptives after relationship formation versus those who were incongruent by “discontinuing” hormonal contraceptives after relationship formation.
These findings suggest that simply using a hormonal contraceptive may not necessarily increase one’s risk of experiencing sexual dissatisfaction in a relationship. Rather, it is hormonal contraceptive incongruency—either beginning or discontinuing the use of hormonal contraceptives after relationship formation—that seems to be associated with future sexual problems.
This work represents an important methodological advancement for research examining the implications of hormonal contraceptive for romantic relationship processes. Although others have previously demonstrated associations between hormonal contraceptive incongruency and relationship processes (for example, relationship satisfaction and jealousy), this paper is the first to do so using a longitudinal design and within-person analyses. Cross-sectional studies have sometimes failed to detect between-person effects of hormonal contraceptive incongruency, and—indeed—when we examined our data using between-person analyses at baseline we also did not detect differences in sexual satisfaction between women who were congruent versus incongruent. Crucially, the longitudinal method and corresponding analyses that we conducted in this paper enabled us to statistically separate those non-significant between-person differences in incongruency from the key significant within-person changes in incongruency that are central to the underlying phenomenon.
We see this as a fruitful starting point for many future research questions. For example, is changing your type of hormonal contraceptive—perhaps by either switching from one brand of The Pill to a different brand or to a different hormonal method such as The Patch—also a form of incongruency? And, if so, are these other potential forms of incongruency also detrimental to relationships?
Without having the longitudinal data to answer these questions, we can only speculate. It seems probable that, yes, there are likely multiple forms of hormonal contraceptive congruency. But the extent to which other forms of incongruency may impact relationship outcomes, such as sexual satisfaction, likely depends on how different the incongruency-related changes actually are. That is, changing from a progestin-only pill to a different progestin-only pill is less of an incongruency than changing from a progestin-only pill to a combination (estrogen and progestin) pill, and the latter is still less of an incongruency than discontinuing hormonal contraceptives altogether.
When women discuss birth control options with their medical doctors, the conversation often revolves around common side effects, such as weight gain, headaches, mood changes, and decreased libido (to name a few). Relational side effects that may occur as a result of changes in hormonal contraceptive use, such as decreases in sexual satisfaction, are less-often (if ever) considered or discussed. There are many factors that contribute to sexual satisfaction—for example, how attracted you are to your partner (which, by the way, hormonal contraceptives may also alter)—and our recent research suggests that hormonal contraceptive incongruency is one such factor. Given the adaptive significance of long-term relationships for humans, it is paramount to understand how modern novelties such as hormonal contraceptives can impact relationship processes and stability.