Preliminary evidence suggests that obsessive-compulsive and related disorder (OCRD) symptoms fluctuate across the menstrual cycle, with consistent premenstrual worsening reported. However, significant research gaps remain, and longitudinal studies with reliable tools are needed to better understand the role of female sex hormones.Anecdotal evidence suggests that the menstrual cycle influences symptoms of Obsessive-Compulsive and Related Disorders (OCRD), although scientific literature investigating this effect is scarce. The premenstrual phase has been associated with the exacerbation of certain psychiatric conditions, with some reports showing premenstrual worsening of OCD. This scoping review aimed to systematically synthesize the evidence on the effect of the menstrual cycle on OCRD symptoms. Systematic searches were conducted on MEDLINE, EMBASE, APA PsycINFO, Cochrane Database of Systematic Reviews, and Web of Science for peer-reviewed studies investigating the menstrual cycle and OCRD. Data examining study methodology, participant demographics, OCRD symptoms, and menstrual cycles were extracted and analyzed.The systematic search identified 12 studies, where ten studies examined OCD symptoms across the menstrual cycle, one examined trichotillomania, and one examined both OCD and trichotillomania. Eight retrospective cross-sectional studies, one longitudinal study were included. Three case reports were identified but not included in the results. Symptom fluctuations were predominantly assessed through self-reports, except for the longitudinal study, which used the Yale-Brown Obsessive Compulsive Scale. In all the studies participants reported worsening OCRD symptoms during the premenstrual phase.Preliminary research suggests OCRD symptoms fluctuate across the menstrual cycle, with premenstrual worsening of OCRD being reported in all studies. Significant gaps exist in the literature emphasizing the need for longitudinal study designs and reliable instruments to improve reliability and clarify the potential relationship between female sex hormones and OCD symptoms.Reference:Juliette S. Mojgani, Anna M. Rzepka, Yejin Kang, Hashim Al-Bya, Beth Patterson, Michael Van Ameringen. The effect of the menstrual cycle on obsessive-compulsive and related disorders: A scoping review, Comprehensive Psychiatry, Volume 147,2026, 152696, ISSN 0010-440X, https://doi.org/10.1016/j.comppsych.2026.152696.(https://www.sciencedirect.com/science/article/pii/S0010440X26000350)Keywords:Study, reports, worsening, symptoms, obsessive-compulsive, disorders , premenstrual, period, Menstrual cycle, Female sex hormones, Premenstrual exacerbations, Obsessive-compulsive disorders, Obsessive-compulsive disorder, Trichotillomania