The Standard Test for Female Sexual Function Holds Up in Pregnancy—But Only in Part

Sexual problems are strikingly common during pregnancy and after childbirth, with prevalence estimates in the perinatal period ranging from 36 to 88 percent. Low desire, difficulties with arousal and lubrication, pain during intercourse, and orgasm problems are all frequently reported by expectant and new mothers. Yet despite decades of research relying on a single questionnaire to measure these experiences—the Female Sexual Function Index, or FSFI—almost nobody had rigorously tested whether the instrument actually works in pregnant and postpartum populations. A new validation study published in Archives of Sexual Behavior by Pablo Santos-Iglesias of Cape Breton University, Natalie O. Rosen of Dalhousie University, and Samantha J. Dawson of the University of British Columbia set out to answer that question, and its findings carry important implications for both researchers and clinicians.

The FSFI has been a workhorse of sexual medicine since its introduction in 2000. The 19-item self-report questionnaire assesses six domains of sexual function over the previous four weeks: desire, arousal, lubrication, orgasm, satisfaction, and pain. Respondents rate each item on a scale, and the domain scores are typically summed into a total score, with a widely used clinical cutoff distinguishing women with and without sexual dysfunction. The instrument was developed and validated in general community and clinical samples of adult women, however—not in people navigating the profound hormonal, anatomical, and relational upheavals of pregnancy and the postpartum period. Whether its scores mean the same thing in those populations had remained largely an open question.

To address it, the research team adopted a contemporary, argument-based approach to validity, guided by modern frameworks that treat validity not as a property of the test itself but of the interpretations and decisions built on its scores. Rather than asking simply whether the FSFI is valid, the researchers examined whether specific claims about what FSFI scores mean in perinatal samples are supported by evidence. This matters because perinatal sexual function is not simply typical sexual function in a different context. Hormonal shifts, tissue changes from delivery, breastfeeding, fatigue, and the psychological transition to parenthood all reshape sexual response in ways that a questionnaire designed for other populations may or may not capture.

The centerpiece of the investigation was a series of factor analyses, statistical techniques that test whether the pattern of people’s answers matches the structure the questionnaire assumes. The results offered a clear verdict on one front: the six-domain structure of the FSFI—desire, arousal, lubrication, orgasm, satisfaction, and pain—was supported in sexually active pregnant and postpartum individuals. In other words, the questionnaire’s underlying architecture holds together in this population, and each domain appears to tap a distinct, coherent aspect of sexual function. That finding gives researchers license to continue using and interpreting the six domain scores with reasonable confidence in perinatal research.

The same could not be said for the total score. Models that assumed a single overarching dimension of sexual function underlying all the items—essentially, the assumption baked into summing everything into one number—were not supported by the data. This is a technically significant result. When a unidimensional model fails, it means the domains are not interchangeable reflections of one common construct, and a total score risks blending genuinely different phenomena into a single, potentially misleading figure. A person might score low overall because of pain alone, for example, while their desire, arousal, and satisfaction remain intact—clinically meaningful distinctions that a total score would obscure. The authors’ conclusion on this point is unambiguous: the use of an FSFI total score is not supported in pregnant and postpartum samples.

Item response theory analyses added a second layer of nuance. These models examine how well each individual item distinguishes between people at different levels of the underlying trait. The findings showed that FSFI items discriminated well at low-to-average levels of sexual function but performed less effectively at higher levels. In practical terms, the questionnaire is most informative for pregnant and postpartum individuals who have poorer sexual function or who are experiencing sexual difficulties. For people functioning well, the items become less precise, meaning small differences among high-functioning individuals may not be reliably captured. This has a silver lining for clinical and research applications focused on identifying and understanding sexual problems, but it cautions against over-interpreting fine-grained differences among people reporting generally healthy sexual function.

The researchers also examined how FSFI domain scores relate to external variables, a standard strategy for testing whether a measure behaves the way theory says it should. With a few exceptions, this evidence indicated that the domain scores are sensitive to real individual differences in sexual function and can distinguish between individuals with and without distressing sexual difficulties. That is, the domains correlate with other measures in sensible ways and show the kind of clinical sensitivity that a useful assessment tool requires. Two domains, however, showed weaker performance: sexual arousal and sexual satisfaction. The authors advise that results from these two domains, like the total score, be interpreted with particular caution in perinatal samples until further evidence accumulates.

The stakes of this psychometric housekeeping are higher than they might appear. Perinatal sexual dysfunction is associated with depression symptoms, relationship dissatisfaction, and distress for both members of a couple, and researchers have increasingly documented trajectories of sexual well-being across the transition to parenthood. Interventions are being developed to support couples’ sexual health during this period, and clinical conversations about resuming intercourse after childbirth depend on accurate assessment. If the field’s dominant measurement tool were quietly mismeasuring these constructs, studies could reach distorted conclusions, clinical cutoffs could misclassify people, and patients’ experiences could be misunderstood. This study provides a foundation of evidence showing which parts of the instrument can be trusted in this population and which cannot.

The work also exemplifies a broader shift in how psychological and sexual health measures are evaluated. Older validation studies often reported a handful of statistics and declared an instrument valid or invalid. Contemporary validity theory, by contrast, builds an integrated argument, weighing evidence from internal structure, item-level performance, and relations to external variables to evaluate specific claims about score interpretation. By applying this framework to the FSFI, the researchers modeled a more rigorous standard for sexuality research, where measurement quality has historically received less scrutiny than in other areas of psychology. The study’s data and analysis code were also made publicly available through the Open Science Framework, supporting transparency and reuse.

For now, the practical guidance is clear. Researchers studying pregnancy and the postpartum period can continue to use the FSFI’s six domain scores as meaningful indicators of the underlying constructs, and the measure appears well suited to identifying individuals with sexual difficulties. But the familiar habit of reporting a single total FSFI score should end in perinatal research, and the arousal and satisfaction domains warrant cautious interpretation. The authors note that further research is needed to address the limitations identified, including the weaker performance at higher levels of function. Until that evidence arrives, this study offers the field something it has long lacked: a clear, evidence-based map of what one of sexual medicine’s most widely used questionnaires can—and cannot—reliably tell us about sexual health during one of life’s most transformative transitions.

Subject of Research: Validation of the Female Sexual Function Index for measuring sexual function in pregnant and postpartum individuals

Article Title: A Validation Study of the Female Sexual Function Index for Use in Pregnant and Postpartum Samples

Article References: Santos-Iglesias, P., Rosen, N. O., & Dawson, S. J. (2026). A Validation Study of the Female Sexual Function Index for Use in Pregnant and Postpartum Samples. Archives of Sexual Behavior, 55(6), 2523-2541. https://doi.org/10.1007/s10508-026-03519-w

Image Credits: AI Generated

DOI: 10.1007/s10508-026-03519-w

Keywords: Female Sexual Function Index, sexual function, pregnancy, postpartum, psychometric validation, factor analysis, item response theory, sexual dysfunction, perinatal health, validity theory, Archives of Sexual Behavior, measurement invariance