In the past decade, researchers have begun to consider what impact hormonal contraceptive use may have on women’s mating psychology. Hormonal contraceptive use reduces naturally occurring cyclical hormonal variance and, as a consequence, women who use hormonal contraception have been shown to display different mating preferences and behaviors than women who are regularly cycling (e.g., Alvergne & Lummaa, 2010; Jones et al., 2008; Penton-Voak et al., 1999). For example, work by Little, Burriss, Petrie, Jones, and Roberts (2013) has demonstrated that, upon initiation of hormonal contraception, women prefer lower levels of masculinity in their male partners. Moreover, these researchers showed that women who met their partner while using hormonal contraception were actually paired with men who had lower levels of masculinity as assessed via both facial measurements and perceptual judgments. This suggests that hormonal contraceptive use has the potential to influence women’s (adaptive) mate preferences (Alvergne & Lummaa, 2010; Roberts, Gosling, Carter, & Petrie, 2008).

Classic research on the impact of hormonal contraceptive use on women’s sexual desire has exclusively examined the impact of current use. Interestingly, these types of studies have produced a very mixed set of findings, with positive, negative, and null results all having been documented (reviewed in Burrows, Basha, & Goldstein, 2012; Pastor, Holla, & Chmel, 2013). To complicate matters further, it is often challenging to compare results from studies examining how women’s use of hormonal contraceptives impacts their sexual desire. For example, studies using samples of young women may be biased in that the initiation of hormonal contraception often coincides with the initiation of one’s first sexual relationship. It would seem inappropriate to compare such studies to the many studies that examine the impact of hormonal contraceptive use on sexual desire in married women. Moreover, comprehensive randomized-controlled studies which examine changes in sexual desire during use of various types and concentrations of hormonal contraception, and use a within-persons design, are lacking. The use of a within-persons design is particularly crucial since women who choose to use hormonal contraception could potentially differ on a number of dimensions from those who choose not to (e.g., socioeconomic status, education level, religious background, sociosexual orientation, relationship status, relationship length).

Given the importance of sexual satisfaction for relationship quality and overall well-being, lack of knowledge, and the mixed associations reported on this topic, are clearly dissatisfying. In light of these findings, we recently proposed the congruency hypothesis as a new framework for understanding how hormonal contraceptive use might impact women’s partner-specific sexual desire (Roberts, Cobey, Klapilová, & Havlíček, 2013, 2014a). We predicted that, because partner preferences differ when regularly cycling and when using hormonal contraception, a woman’s current level of sexual desire for her partner may be partially dependent on whether her current use/non-use of contraception is congruent with her use at the time at which she began her relationship. Thus, if a woman’s hormonal contraceptive use has changed since the time of partner choice, her mate preferences will be somewhat different, and therefore we predicted she may experience a moderate decrease in desire for her partner since he may no longer match her preferences as closely. However, we predicted that hormonal contraceptive congruency would not impact women’s sexual desire for extra-pair men since women can easily adjust the target of their extra-pair interest or fantasy. That is to say, if a woman’s mate preferences shift, she may continue to show consistent levels of general sexual desire to men other than her partner: she can easily find someone new in her environment who matches her new preferences. In contrast, since a woman’s partner is constant, if her mate preferences change, her sexual interest for him may change. To examine this possibility, it is necessary to distinguish the object of sexual desire (partner-focused vs extra-pair); a distinction that is rarely made in existing research (Roberts et al., 2014a).

Recent empirical research testing the congruency hypothesis has provided support for its premises. Roberts et al. (2014b) showed that women whose current contraceptive use was congruent with use at the start of the relationship had higher levels of sexual satisfaction in their relationship. Importantly, effects of congruency in this study did not extend to non-sexual aspects of the relationship. This finding supports earlier work by Roberts et al. (2012) who found that, among women who were currently regularly cycling, those who met their partner on the pill were less sexually satisfied and had lower levels of partner attraction than those who met while regularly cycling. Interestingly, however, these same women who met their partner on the pill were more satisfied with his provision of parental care than were those women who met their partner while regularly cycling. This finding may be explained by the fact that masculine traits, which are preferred at reduced levels when using hormonal contraception, tend to be associated with lower levels of paternal care (Boothroyd, Jones, Burt, & Perrett, 2007). These results appear to suggest that contraceptive use/non-use at the start of the relationship has implications for subsequent relationship satisfaction. In other work, we have also provided preliminary evidence that contraceptive congruency may impact other aspects of one’s relationship beyond sexual and romantic relationship satisfaction, including levels of sexual jealousy (Cobey, Roberts, & Buunk, 2013).

The current research was developed as an extension of the literature outlined above and in order to test the predictions of the congruency hypothesis. Here, we aimed to test how use/non-use of hormonal contraception at the time of relationship initiation is related to sexual desire levels during subsequent pregnancy. Pregnancy is a distinctive time for couples, and the combination of physical and emotional changes occurring may have consequences for both general and sexual aspects of the relationship. Previous research has demonstrated mixed results with respect to how pregnancy influences relationship quality and sexual satisfaction. For example, meta-analyses indicate that pregnant women exhibit substantial inter-individual variability, particularly in the second trimester, with respect to their sexual responsiveness, coital frequency, and sexual satisfaction (von Sydow, 1999). We suggest that the congruency hypothesis could potentially contribute toward explaining some of this variance.

Since hormonal changes across the cycle or as a result of hormonal contraceptive use impact women’s sexual desire and mating preferences, it is reasonable to presume that as a result of hormonal variation, pregnant women also experience changes in their social perception and thus in partner preferences. Pregnancy is maintained by hormonal changes; perhaps most notably, it is characterized by rapid changes in levels of estrogen and progesterone, which rise continuously from conception to parturition. At present, there is preliminary evidence to suggest that partner preferences when pregnant resemble those predominant during hormonal contraceptive use. For example, Jones et al. (2005) showed that women who were using hormonal contraceptives, or who were pregnant, have a stronger preference for healthy-looking faces than women who were regularly cycling. Thus, based on this literature, we hypothesized that a pregnant woman who met her partner while using hormonal contraception would have partner preferences that were more congruent than a pregnant woman who met her partner while regularly cycling. As a consequence, we expected that: (1) Women who met their partner while using hormonal contraception would display higher levels of sexual desire toward their partner during pregnancy than those who met their partner when regularly cycling; (2) In contrast, women’s sexual desire during pregnancy for extra-pair men would not relate to contraceptive congruency since women can adjust the target of their extra-pair interest.