Once upon a time, polycystic ovary syndrome (PCOS)—a reproductive and metabolic multisystemic condition with impacts across the lifespan—was a broad diagnostic term capturing a group of women, not all of whom fit neatly into a single category. As research and clinical understanding advances, we now know there are meaningful ways to subdivide the diagnosis and that this greater specificity can impact intervention selection and success. Unsurprisingly, lifestyle interventions including nutrition support are considered some of the most important and effective, but improved understanding of subtypes may help guide those treatment approaches more precisely.
PCOS affects roughly 11% to 13% of women worldwide.1 Although PCOS famously can negatively impact fertility, its consequences don’t stop there, revealing a complex pathophysiology that touches multiple systems and can introduce different metabolic dysregulations throughout the body. The most common symptoms of PCOS include menstrual dysfunction, infertility, hirsutism, acne, and obesity.2 However, so-called “lean type” PCOS is increasingly recognized and these patients often present with a favorable metabolic profile. By contrast, obese PCOS patients typically have higher blood pressure, blood lipid, and blood glucose levels. Importantly, insulin resistance is a key feature of PCOS, and obesity has been implicated in the pathogenesis of this condition.3 Even so, studies also indicate that when compared with the general population, lean PCOS patients are at a higher risk of developing metabolic disorders. Even if their body weight is within the normal range, they may have underlying metabolic problems such as mild insulin resistance or abnormal lipid metabolism.3
In a recent study published in 2025 in Nature Medicine,1 researchers applied advanced data analysis techniques in parsing and interpreting collections of clinical variables in PCOS. What they found added to a growing body of research creating a compelling case for four distinct PCOS subtypes:
- The hyperandrogenic subtype (HA-PCOS, 25%) was characterized by high testosterone-dehydroepiandrosterone sulfate (DHEA-S), along with mild metabolic disorders.
- The subtype with obesity (OB-PCOS, 26%) was characterized by higher BMI, fasting glucose, and fasting insulin level, with the highest prevalence of type 2 diabetes (7.9%), dyslipidemia (75.3%), and hypertension (28.7%).
- The high-sex hormone-binding globulin subtype (SHBG-PCOS, 26%) had the highest sex hormone-binding globulin (SHBG) level and lowest BMI among four subtypes, primarily manifested as lower luteinizing hormone (LH) and testosterone levels.
- The high-LH–AMH subtype (LH-PCOS, 23%) was distinguished by elevated levels of LH, follicle-stimulating hormone and anti-Müllerian hormone (AMH).1
A Note About Diagnosis
To diagnose PCOS, it is recommended to use the modified Rotterdam criteria,4 where PCOS may be diagnosed if any two of the following are present:
- clinical or biochemical hyperandrogenism;
- evidence of oligo-anovulation; and/or
- polycystic-appearing ovarian morphology on ultrasound, with exclusion of other relevant disorders.
The Rotterdam criteria were named for a 2003 conference that took place in Rotterdam, the Netherlands, sponsored by both the European Society of Human Reproduction and American Society for Reproductive Medicine, and produced a joint consensus statement. These criteria broadened the earlier diagnostic criteria to allow for the diagnosis of PCOS without hyperandrogenism, which had previously been viewed as the primary defect by the 1990 National Institutes of Health (NIH) criteria.4
In 2012, the NIH held an evidence-based methodology workshop on PCOS, in which experts on PCOS recommended use of the 2003 Rotterdam criteria, while specifically identifying subphenotypes within these criteria of 1) androgen excess and ovulatory dysfunction, 2) androgen excess and polycystic ovarian morphology (PCOM), 3) ovulatory dysfunction and PCOM, and 4) androgen excess, ovulatory dysfunction, and PCOM. The Rotterdam criteria, which were unanimously supported in the 2018 International Evidence-Based Guideline for the Assessment and Management of PCOS, continue to be the most widely used and accepted criteria for PCOS.4
Subtypes and Outcomes
Researchers from the 2025 study validated the subtypes in five independent cohorts of different ethnicities from China, the United States, Europe, Singapore, and Brazil. In addition, they examined the association between reproductive and metabolic variables in different subtypes during a 6.5-year follow-up, and of in vitro fertilization (IVF) outcomes and pregnancy complications among the subtypes.1
A total of 4,542 women with PCOS diagnosed between 2014 and 2018 in the discovery cohort were followed up by telephone interviews, and 523 of them voluntarily underwent physical examinations. The average age of these participants was 34 years.1
Researchers assessed remission status of PCOS at the time of the follow-up visit. According to physical examination data at the follow-up visit, the percentages of women in the four subtypes who still met the Rotterdam criteria were 67.2% for HA-PCOS, 50.9% for OB-PCOS, 52.8% for SHBG-PCOS, and 74.8% for LH-PCOS.1
The cumulative incidence of chronic metabolic complications was also compared among the four subtypes. HA-PCOS had the highest incidence of dyslipidemia (24.4%), whereas OB-PCOS exhibited the highest incidence of T2DM (16%). The incidence of hypertension was higher in HA-PCOS (11.1%) and OB-PCOS (14.6%) than in the other two subtypes. Remarkably, SHBG-PCOS demonstrated better metabolic characteristics, with the lowest incidence of type 2 diabetes and hypertension.4
According to the authors, although the Rotterdam criteria have improved prognostic capacity for predicting reproductive outcomes in women with PCOS, they may overlook some key heterogeneities that result in potentially severe complications. They believe that incorporating these more specific phenotypic data can further improve outcomes. They developed PcosX (www.pcos.org.cn), a web-based tool designed to assign women with PCOS to specific subtypes, provided the necessary clinical variables have been measured.
Compared with other subtypes, women with OB-PCOS are more prone to pregnancy complications, including hypertensive disorders, gestational diabetes, preterm birth, and cesarean delivery.
SHBG-PCOS is considered the mildest form of PCOS and has the best IVF outcomes, although it often presents with irregular cycles or PCOM. It appears to exhibit relatively mild neuroendocrine, androgenic, and metabolic dysregulations, with primary abnormalities related to ovulatory dysfunction. SHBG, produced by the liver, binds to circulating sex steroids, affecting their bioavailability by sequestering androgens and estrogens from biological action. Several clinical studies have highlighted the potential role of SHBG in maintaining glucose homeostasis, because low levels of SHBG are strongly associated with an increased risk of type 2 diabetes.
LH-PCOS showed the poorest disease remission of PCOS at follow-up, suggesting that the effects of high LH and AMH levels on PCOS may not be improved by IVF procedures. Moreover, special attention should be given to the LH-PCOS subtype, because it is associated with the most typical reproductive characteristics of PCOS and carries an exceptionally high risk of ovarian hyperstimulation syndrome.
The authors emphasize that this data is just the beginning of the long process of understanding the complexity of the PCOS subtypes and more research is needed.
Lifestyle Interventions
A considerable amount of research has looked at the potential role of environmental pollutants such as heavy metals, insecticides, and endocrine disrupting chemicals in reproductive dysfunction, including their influence on PCOS development. BPA exposure has been a particular concern. Additionally, some research has noted that women with PCOS may also have impaired xenobiotic metabolism.2 The biotransformation pathways in the body that help bind and excrete xenobiotics are impacted by genetic single nucleotide polymorphisms as well as nutrition status. Nearly every single micro- and macronutrient has a role to play in supporting these critical pathways.
Polycyclic aromatic hydrocarbons produced from cigarette smoke, burnt coal, gas, wood, garbage, and meat cooked at high temperatures constitute a major part of the air pollutants that are positively correlated with the risk of developing PCOS.2
Given the propensity for glucose and insulin dysregulation in every PCOS subtype to varying degrees, it’s no surprise that interventions prioritizing blood sugar management, including lower glycemic load diets had positive effect.2
Gut health is also commonly compromised in those with PCOS, with higher propensity for dysbiosis and related concerns. For example, studies have shown microbiome tendencies in PCOS toward a decrease in beneficial bacteria (lactobacilli and bifidobacteria) and an increase in pathogenic bacteria (Escherichia and Shigella).2
Nutrition interventions are uniquely elegant solutions as one powerful tool in the toolbox for interdisciplinary clinical support for PCOS patients. Nutrient imbalances may not only contribute to altered hormone metabolism directly, but indirectly through influencing inflammatory signaling, detoxification or biotransformation pathways, microbiome health, and glucose regulation—among many others.
Some research has emphasized the importance of calcium and vitamin D in PCOS, where restoring adequate intake (where it was previously insufficient) alongside metformin was associated with improved menstrual regularity and follicular maturation, significantly reduced serum insulin levels, fasting blood sugar, and significantly increased the quantitative insulin sensitivity check index. Additionally, it decreased hirsutism and testosterone levels, serum triglycerides and VLDL-C levels, and cholesterol as well as LDL levels in PCOS patients.2
Takeaways
Precision nutrition as it might be applied to individual PCOS subtypes is a science still in its infancy. However, an argument could certainly be made for prioritizing interventions more aggressively in those with more severe subtypes or greater risk for complications, including pregnancy-related complications. Dietitians are highly important care team members for PCOS patients, providing evidence-based custom nutrition support that meets each patient where they are at. Those with PCOS may also be at an increased risk for disordered eating, with as much as a three- to six-fold increased risk.5 RDs can provide comprehensive care alongside other providers to ensure each PCOS patient is treated as the individual they are.
— Heather Davis, MS, RDN, LDN, is editor of Today’s Dietitian.
References
1. Gao X, Zhao S, Du Y, et al. Data-driven subtypes of polycystic ovary syndrome and their association with clinical outcomes. Nat Med. 2025;31(12):4214-4224.
2. Singh S, Pal N, Shubham S, et al. Polycystic ovary syndrome: etiology, current management, and future therapeutics. J Clin Med. 2023;12(4):1454.
3. Zheng C, Lin Y, Zhang Z, Ye J, Lin Y, Tian J. Analyzing and evaluating the metabolic and endocrine characteristics between lean and obese patients with polycystic ovary syndrome: a systemic review and meta-analysis. Front Endocrinol (Lausanne). 2025;16:1680685.
4. Christ JP, Cedars MI. Current guidelines for diagnosing PCOS. Diagnostics (Basel). 2023;13(6):1113.
5. Lalonde-Bester S, Malik M, Masoumi R, et al. Prevalence and etiology of eating disorders in polycystic ovary syndrome: a scoping review. Adv Nutr. 2024;15(4):100193.