Sexual Functioning and Its Determinants in Couples with Unexplained Infertility

25% of women and 7% of men newly diagnosed with unexplained infertility screen positive for sexual dysfunction

Journal: Human Reproduction | Published: 2026-Mar-01 | Type: Cross-sectional survey (RCT baseline) | PMID: 41527942 Authors: Dreischor F et al. (Amsterdam UMC Centre for Reproductive Medicine; KU Leuven; Maastricht UMC+; Franciscus Hospital Rotterdam) Funding/COI: Netherlands Organization for Health Research and Development (ZonMW), University of Amsterdam, Flanders Research Foundation — funders had no role in design or analysis. C.B. Lambalk was Editor-in-Chief of Human Reproduction until recently and has received speakers' honoraria and travel support from Merck and Organon.

Summary

A cross-sectional survey of 700 Dutch heterosexual couples newly diagnosed with unexplained infertility found that roughly 1 in 4 women (24.3%) and 1 in 14 men (7.3%) scored above clinical cut-offs for sexual dysfunction on the FSFI and IIEF respectively. Anxiety and depression were the strongest individual predictors of impaired sexual functioning in both sexes, with anxiety conferring a fourfold increase in odds of female sexual dysfunction (OR: 4.22). A curious outlier: higher total motile sperm count was associated with worse female sexual functioning — a counterintuitive finding the authors do not fully explain.

Claims

• 24.3% of women met the FSFI threshold for female sexual dysfunction risk; 7.3% of men met the IIEF threshold for erectile dysfunction risk
• Mean coital frequency was 7 times per month (SD: 2.7)
• Higher sexual desire and satisfaction — but not orgasm — were significantly associated with increased coital frequency in both partners
• Female sexual dysfunction was associated with: own age (OR: 1.12 per year), anxiety (OR: 4.22), depression (OR: 3.23), relationship distress (OR: 2.04), and total motility sperm count (β: −4.88)
• Male sexual dysfunction was associated with: own anxiety (β: −5.03), depression (β: −3.65), relationship distress (β: −5.77), partner's age (β: −0.46), and longer infertility duration (OR: 1.06)
• Complete couple-level data were available for 451 of the 700 enrolled couples (64.4%)

Study Quality

This is a cross-sectional design, so it can establish association but not causation. That said, the methodology is above average for this literature: the team used validated instruments throughout (FSFI, IIEF-15, Hospital Anxiety and Depression Scale, Revised Dyadic Adjustment Scale) and applied dyadic analysis — an actor-partner interdependence model — rather than treating each partner's data independently. That matters because sexual functioning in couples is inherently interdependent, and most prior work ignores that.

Sample size is reasonable for a couples study: 581 women and 478 men returned usable questionnaires, with 451 complete dyads. Funding was independent, and the study was pre-registered as the baseline of the Pleasure&Pregnancy RCT (NTR5709), which means longitudinal follow-up data will eventually exist.

Red Flags

• Selection bias is real and significant. These are couples who sought specialist care, agreed to randomization in an RCT, and were able to have coitus — a triply filtered sample. Prevalence estimates almost certainly do not generalize to the broader unexplained infertility population.
• Heterosexual couples only. The instruments used (FSFI, IIEF) are validated for heterosexual dyads. Findings say nothing about same-sex couples.
• The sperm quality finding is unexplained. Higher total motile sperm count predicting lower female sexual functioning (β: −4.88) is counterintuitive. No mechanism is proposed. Could be a statistical artifact, a confound with male age, or reflect some relational dynamic — but the paper doesn't dig in.
• Cross-sectional design. Nothing here establishes that infertility caused the sexual dysfunction. Anxiety and depression may predate the infertility diagnosis.
• Missing data not formally handled. The authors acknowledge some previously identified determinants were not assessed due to missing data or low case numbers. No imputation strategy is described.
• Lambalk COI. Industry honoraria from Merck and Organon are disclosed but not contextualized — Organon manufactures fertility drugs. This paper isn't about treatment, but the disclosure warrants notice.

Strengths

• Dyadic analysis correctly models partner interdependence rather than treating individuals as independent observations
• Validated, widely-used instruments for both sexual function and psychological well-being
• Independent public funding with explicit statement that funders had no role in analysis
• Pre-registered as RCT baseline — longitudinal data forthcoming
• Large relative to prior couples-focused sexual function studies in this population
• Reports actual effect sizes and confidence intervals, not just p-values

Verdict

This is a solid piece of epidemiology for a literature that has historically been thin. The 25% female sexual dysfunction rate is the kind of concrete number that fertility clinics should have in their heads when counseling couples toward "wait and try naturally." The anxiety-dysfunction association (OR 4.22 for women) is strong enough to take seriously even given the cross-sectional design. The unexplained sperm quality finding is a genuine loose end that future work from this RCT might resolve. Don't treat the prevalence estimates as population-level truth — the sample is too filtered for that — but as a signal about the couples sitting in infertility waiting rooms, this paper earns its place.