Testing the congruency hypothesis using meta-analysis: Are changes in oral contraceptive use correlated with...

Based on claims that changes in women's hormone levels influence their mating psychology, the Congruency Hypothesis proposes that women in relationships who change their hormonal contraceptive use after meeting their partner will report lower sexual satisfaction with their partner than women who do not change their oral contraceptive use. However, findings from studies testing this hypothesis have reported mixed results. Consequently, we conducted a meta-analysis of published studies on this topic. For the thirteen effects sizes from studies using between-subjects designs, the pooled correlation between congruency and sexual satisfaction was not statistically significant (r = 0.04, p = .091) and a Robust Bayesian meta-analysis found that the null hypothesis was moderately favoured over the Congruency Hypothesis (BF₁₀ = 0.123, i.e., BF₀₁ = 8.13, r = 0.003). For the four effect sizes from studies using within-subjects designs, the pooled correlation between congruency and sexual satisfaction was statistically significant (r = 0.18, p = .001) and a Robust Bayesian meta-analysis found weak evidence in favour of the Congruency Hypothesis (BF₁₀ = 1.55, r = 0.09). Although the effect of congruency on sexual satisfaction may be statistically significant in some analyses, across all analyses, results indicated that the magnitude of the congruency effect was small. Thus, we suggest that it is unlikely that changes in oral contraceptive use have a substantial (i.e., large) effect on women's sexual satisfaction on average. Still, some women might experience congruency effects and the overall evidence remains uncertain. More work, ideally in the form of randomized controlled trials, is needed to find a definite answer for research questions relying on the Congruency Hypothesis.