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Background: Polycystic ovary syndrome (PCOS) is the most common reproductive disorder in women affecting 1 and 8 reproductive age women worldwide. PCOS is based on the presence of two or more cardinal features including ovulatory dysfunction, hyperandrogenism and polycystic ovarian morphology. Ethnic and racial variations in the clinical presentation of PCOS have been reported suggesting that screening and diagnosis of PCOS may require consideration of regional differences in reproductive symptomology. Little to no data exist on the potential for geographic variations in polycystic ovarian morphology on ultrasonography. As such, the utility of the current international standard for defining polycystic ovaries is in question. Study Question: Are there differences in ovarian morphology between India- and United States-based women with PCOS? Objective and Rationale: To determine whether ovarian morphology differs between women with PCOS from two different geographic regions of the globe in order to support the appropriateness of a singular international standard to define polycystic ovarian morphology. What is Known Already: The International Evidence-Based Guideline for the Assessment and Management of PCOS supports phenotypic differences in the presentation of PCOS, including variations in the reproductive and cardiometabolic profiles among women of different races and ethnicities. However, few studies have directly contrasted clinical, endocrine and morphological variables across races, ethnicities and/or geography. Study design, Size, Duration: A retrospective, cross-sectional analysis of de-identified research and medical records from women with PCOS collected between 2010 to 2022 from two geographic regions (India and the United States) was performed. The study population comprised a total of 331 reproductive age (18-38 years) women with PCOS for which both an ultrasound scan of the ovaries and clinical data to corroborate a PCOS diagnosis were available. Participants, Setting, Methods: In India, data for inclusion were available for 119 women with PCOS attending a gynecological practice for evaluation and treatment of reproductive disorders. In the United States, data for inclusion were available from 212 women with PCOS that engaged in a research study across three clinical research centers in New York State. Two sample t-tests and chi-square or Fisher’s exact tests were used to assess differences in continuous and categorical variables across groups, respectively. Bivariate Pearson correlation analysis was used to determine any correlations between ovarian morphology markers with reproductive and metabolic features for the two geographical groups. Main Results: Ovulatory dysfunction as judged by menstrual irregularity was more prevalent in India-based women compared to U.S.-based women, with a greater majority reporting cycles greater than 35 days (99 vs. 87%, p<0.0001). Likewise, a higher prevalence of hyperandrogenism was apparent in India- versus U.S.-based women with PCOS (99% vs. 52%, P<0.0001). Both the proportion of those with elevated testosterone (45% vs. 17%) and Ferriman-Gallwey scores greater than 6 (100% vs. 43%) were higher in the India-based group compared to U.S.-based participants, with a difference also noted in the severity of hirsutism scores (all P<0.001). Nearly all participants in both groups met the criteria for polycystic ovarian morphology (99%) with the India-based group demonstrating a higher prevalence of follicle excess compared to the U.S.-based group (94% vs. 86%, p = 0.039). Prevalence of ovarian enlargement was similar across groups (India 71% vs. United States 70%, p=0.900). Further, follicle number per ovary (35.3 ±13.4 vs. 39.1 ±20.6), follicle number per single cross-section (8.8 ±2.8 vs. 9.6 ±4.0), and ovarian volume (9.0 ± 3.9 vs. 8.8 ± 4.4) did not differ between India- and -U.S.-based groups (all p>0.05). Of the non-conventional ovarian features assessed, stromal area (4.3 ± 1.4 vs. 4.2 ±1.4), and stromal to ovarian area ratio (0.8 ± 0.1 vs. 0.8 ± 0.1), did not differ between groups – albeit ovarian area was slightly larger in women with PCOS from India (6.3 ±1.7 vs. 6.0 ±1.8, p=0.030). Collectively, a vast majority of participants from India met the criteria for Frank PCOS whereas U.S.-based participants had a more heterogeneous phenotypic presentation, with a majority having a Mild variant of PCOS. Subgroup analyses of women meeting the criteria for Frank PCOS confirmed little to no variations in ovarian size and stromal characteristics across the India- and U.S.-based groups. However, follicle number per ovary (48.6±23.2 vs. 35.9± 13.2, P<0.0001) and follicle number per single cross-section (10.9±3.9 vs. 8.9±2.7 p=0.0003) were higher in the U.S.- versus India-based group, respectively. Associations between ovarian morphology and reproductive markers [menstrual cycle length (ρ= 0.16 – 0.25), Ferriman-Gallwey hirsutism scores (ρ= 0.16 – 0.26), and/or total testosterone (ρ= 0.24 – 0.34)] were noted in both the U.S.- and India-based group on both the full and subgroup analysis (all, p<0.05). By contrast, associations detected between ovarian morphology and metabolic status markers (fasting blood glucose (ρ= -0.29 – 0.31), diastolic blood pressure (ρ= -0.24 – -0.26), body mass index (ρ= 0.12 – 0.32), triglycerides (ρ= 0.18 – 0.34), and HDL (ρ= -0.12 – -0.33), were inconsistent across both groups with additional associations emerging in the subgroup analysis (2-hour glucose (ρ= -0.29 – 0.31), and waist to hip ratio (ρ= -0.31 – 0.43). Limitations, Reasons for Caution. Ultrasonographic scans from India were conducted either post-natural menses or after a progesterone-induced bleed whereas, scans conducted in the U.S. never occurred following progesterone stimulation. While all scans were conducted in the follicular phase, we cannot exclude the possibility that progesterone withdrawal in a subset of participants in India impacted morphological findings across groups. Different biochemical assays were used across geographic regions. Since metabolic marker assays used for both groups were not comparable, analyses were run separately for each region, thereby restricting the analyses to subgroup regression analyses (India and U.S.). Participants were evaluated in different settings (i.e., research center versus clinical practice). Therefore, differences in PCOS symptomology between groups may relate to a higher likelihood of severe clinical manifestations presenting primarily to a clinical practice rather than a research setting. Lastly, data from healthy women with regular cycles were not available for inclusion across both sites. Therefore, the generation of regional-specific criteria for polycystic ovarian morphology and their performance could not be directly evaluated. Conclusion and wider implications of the findings: Geographic differences exist in the clinical presentation of PCOS. However, variations in ovarian morphology may not be sufficient to warrant regional definitions of polycystic ovarian morphology. Ovarian dysmorphology served as a biomarker of the severity of reproductive symptomology in both regions consistent with the ovary being a central component of the pathophysiology of PCOS. However, more research is needed to fully elaborate its utility as a marker of metabolic status across races and ethnicities.

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62 pages


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2018 International Guideline; Geography; Metabolic Syndrome; Ovarian Morphology; Polycystic Ovary Syndrome; Rotterdam Criteria


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Union Local


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Lujan, Marla

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Ren, Yi

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M.S., Nutrition

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Master of Science

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Attribution 4.0 International


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