Impact of Hypocaloric Dietary Intervention on Phenotypic Presentations of Polycystic Ovary Syndrome (PCOS)

Background/Objective: Lifestyle intervention is recommended as first-line treatment for polycystic ovary syndrome (PCOS). This pilot study aimed to determine if a short-term hypocaloric dietary intervention induced changes in the phenotypic presentation of PCOS. Methods: Twenty women with PCOS and overweight/obesity participated in a 3-month hypocaloric dietary intervention with a 6-month follow-up. At pre-intervention, post-intervention, and follow-up, assessments of menstrual cycle status, hyperandrogenism, and polycystic ovarian morphology were performed, and PCOS phenotype status was determined using the following scale of decreasing severity: Phenotype A (ovulatory dysfunction, hyperandrogenism, and polycystic ovaries), Phenotype B (ovulatory dysfunction and hyperandrogenism), Phenotype C (hyperandrogenism and polycystic ovaries), or Phenotype D (ovulatory dysfunction and polycystic ovaries). Results: The participants lost 8 ± 3% of their initial body weight with the intervention (p < 0.001). Eight (40%) participants experienced a favorable shift in PCOS phenotype, while the remaining 12 (60%) participants had an unfavorable shift or no change. Changes in PCOS phenotype were primarily driven by reductions in menstrual cycle length (p = 0.010) and follicle number per ovary (p = 0.017), albeit no baseline clinical variable predicted a favorable-change PCOS presentation. At the 6-month follow-up (N = 12), weight was increased (p < 0.05), and seven participants (58%) had reverted to a more severe phenotype. Conclusions: Weight loss may provide temporary improvement in the phenotypic presentation of PCOS, yet sustained lifestyle change may be required to maintain these benefits.