Mental health of couples affects fertility, modified by socioeconomic status: a couple-based analysis.

study questionDoes preconception mental health status in either partner affect fertility and infertility, and is this association modified by socioeconomic status (SES)? SUMMARY ANSWER: Preconception mental health problems in both partners are associated with lower couple fertility, with the synergistic impact being most pronounced among couples with low SES status. WHAT IS KNOWN ALREADY: Mental health problems are rising among young adults, and fertility rates are declining. Women's preconception mental health has been linked to lower fertility, but few studies have examined the combined impact of both partners' mental health. The modifying role of SES in these associations is also poorly understood. STUDY DESIGN SIZE DURATION: This couple-based prospective cohort study included 966 preconception couples who sought preconception care and were followed for 12 months in the Shanghai Birth Cohort between 2013 and 2015. PARTICIPANTS/MATERIALS SETTING

methodsThe couples' mental health status was evaluated at enrolment using the Center for Epidemiological Studies-Depression Scale, Zung Self-Rating Anxiety Scale, and Perceived Stress Scale. The outcomes included couple fecundability (measured by the TTP) and infertility (i.e. TTP >12 menstrual cycles). In the partner-specific model, Cox proportional hazards models and logistic regression were used to evaluate the associations between each partner's depression, anxiety, and stress levels and couples' fertility. In the couple-based model, cross-classification and quantile g-computation were first applied to identify couples' joint exposure to specific psychological conditions in relation to fertility. Latent profile analysis (LPA) was then conducted to characterize distinct latent profiles of couples' overall mental health statuses, followed by Cox proportional hazards models and logistic regression to examine the corresponding associations. Key symptoms in the couples' depression, anxiety, and stress scales were determined by elastic net regression and least absolute shrinkage and selection operator. To assess the potential effect modification of SES on the association between couples' mental health and fertility, we conducted stratified analyses by male and female partner education levels and household income. MAIN RESULTS AND THE ROLE OF CHANCE: In the female partner-specific model, a 1 SD increase in depression score was associated with 10% lower fecundability (FOR = 0.90, 95% CI: 0.82, 0.99). Likewise, a 1 SD increase in the stress score was associated with 13% lower fecundability (FOR = 0.87, 95% CI: 0.79, 0.96). Male anxiety was associated with a higher risk of infertility (OR = 1.19, 95% CI: 1.01, 1.42). Stratified analyses showed that depression, anxiety, and stress were significantly associated with lower fecundability among males with an education level <college (FOR = 0.79-0.73) and stress was significantly associated with lower fecundability among females with an education level <college or family income <Chinese Yuan 150 000/year (FOR = 0.77). In the couple-based cross-classification model, couples in which both partners reported stress had a 24% lower fecundability (FOR = 0.76, 95% CI: 0.60, 0.96) compared with couples with no stress symptoms. LPA identified seven distinct patterns of couples' mental health status. Compared with the 'Neither partner with symptoms' group, the 'Female-high/Male-medium' group showed 56% lower fecundability, followed by 23% lower fecundability in the 'Female-medium/Male-medium' group. The greatest attributable impact of the couples' mental health composite score was observed among couples in which both partners had <college education, accounting for 19.0% of infertility cases. LIMITATIONS REASONS FOR CAUTION: Potential reporting and recall biases, residual confounding from unmeasured factors such as antidepressant or other medication use, and prior history of depression, anxiety, and stress were not controlled for. Additionally, mental health was assessed only at baseline, limiting our ability to examine the effects of longitudinal changes in mental health status on fertility outcomes. WIDER IMPLICATIONS OF THE

findingsThis study highlights the importance of addressing the mental health of both partners before conception to improve fertility, particularly among couples with lower SES. Integrating mental health care into preconception services may help lower infertility and related disparities. STUDY FUNDING/COMPETING INTERESTS: This study was partly supported by the National Key R&D Program of China (2023YFC2705501 and 2023YFC3905203) and the National Natural Science Foundation of China (41991314). All authors declare no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.