Understanding polyendocrine metabolic ovarian syndrome (PMOS), its effects on fertility and pregnancy, and why comprehensive preconception care can improve the foundation for maternal and child health.
For many women, the journey toward pregnancy begins with questions about menstrual cycles, ovulation, fertility, and reproductive hormone levels.
When those processes become disrupted, attention naturally turns toward the reproductive system. Conditions such as polycystic ovary syndrome (PCOS) are often discussed in relation to irregular menstruation, elevated androgen levels, and difficulties conceiving.
But what if the reproductive symptoms are only one part of a much larger physiological picture?
Emerging research demonstrates that PCOS involves complex interactions among the brain, ovaries, pancreas, liver, adipose tissue, immune system, and metabolic regulatory pathways.
These interactions can influence not only ovulation and fertility but also cardiovascular health, glucose regulation, inflammation, pregnancy complications, and potentially the long-term health of offspring.
In 2026, a major review published in Nature Reviews Endocrinology, titled Polyendocrine Metabolic Ovarian Syndrome in Pregnancy: Pathophysiology and Outcomes, examined these relationships and their clinical implications.
The review also reflects an important change in terminology: polycystic ovary syndrome has been renamed polyendocrine metabolic ovarian syndrome (PMOS) following an international consensus process.
This change recognizes that the condition is not simply an ovarian disorder. It is a lifelong, multisystem endocrine and metabolic condition with important implications for women's health.
Understanding these relationships provides a foundation for a more comprehensive approach to fertility, preconception health, and pregnancy.
Why Is PCOS Now Called Polyendocrine Metabolic Ovarian Syndrome?
For decades, the term polycystic ovary syndrome has contributed to a misunderstanding of the condition.
The word "polycystic" suggests that ovarian cysts are the defining feature of the disorder.
In reality, the characteristic ovarian findings generally involve numerous small follicles rather than pathological ovarian cysts. Moreover, not every woman with the condition demonstrates polycystic ovarian morphology.
The condition also involves metabolic and endocrine abnormalities extending well beyond the ovaries.
These may include insulin resistance, hyperinsulinemia, hyperandrogenism, disturbances in hypothalamic-pituitary-ovarian signaling, adipose tissue dysfunction, and chronic low-grade inflammation.
A 2026 article in Nature Metabolism, Polyendocrine Metabolic Ovarian Syndrome—A New Name for an Old Problem, explains how the updated terminology better reflects these broader physiological relationships.
The name PMOS emphasizes three important characteristics:
Polyendocrine: Multiple endocrine organs and hormonal pathways participate in the condition.
Metabolic: Insulin signaling, glucose metabolism, adipose function, and cardiometabolic health are central components.
Ovarian: Ovulatory dysfunction and ovarian hormone regulation remain clinically important features.
Although the terminology is changing, many patients and healthcare professionals will continue to recognize the condition as PCOS.
The underlying message, however, is clear:
PMOS is more than an ovarian or fertility problem. It is a systemic condition involving interconnected endocrine, metabolic, inflammatory, and reproductive processes.
Understanding the Endocrine and Metabolic Mechanisms of PMOS
To understand why PMOS can affect pregnancy, we first need to examine its underlying physiology.
Reproductive function depends on coordinated signaling between the hypothalamus, pituitary gland, and ovaries.
The hypothalamus releases gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to produce luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
These hormones regulate ovarian follicular development, ovulation, and reproductive hormone production.
In PMOS, altered neuroendocrine signaling can contribute to increased LH activity, excessive androgen production, and impaired follicular maturation.
These changes may interfere with ovulation and produce menstrual irregularity.
However, the reproductive system does not operate independently of metabolism.
Insulin Resistance and Hyperinsulinemia
One of the most important metabolic features of PMOS is insulin resistance.
Insulin helps regulate blood glucose by facilitating glucose uptake and coordinating metabolic processes across tissues.
When insulin sensitivity declines, the pancreas often compensates by producing additional insulin.
This compensatory hyperinsulinemia can influence ovarian hormone production.
Elevated insulin concentrations may amplify ovarian androgen production and reduce hepatic production of sex hormone-binding globulin (SHBG), increasing the proportion of circulating biologically available androgens.
These changes can reinforce ovulatory dysfunction and other features of PMOS.
Importantly, insulin resistance can occur in women with PMOS even when their body mass index is within a conventional reference range.
A 2025 review in Nature Reviews Endocrinology, Polycystic Ovary Syndrome as a Metabolic Disease, emphasized the importance of metabolic dysfunction across different PMOS phenotypes.
This means that metabolic assessment should not be based exclusively on body weight.
Hyperandrogenism and Reproductive Function
Androgens, including testosterone, are normal components of female physiology.
However, excessive androgen activity can contribute to symptoms such as acne, increased facial or body hair, and irregular ovulation.
Hyperandrogenism can also interact with insulin resistance, follicular development, and endometrial function.
These relationships help explain why PMOS may affect fertility through several mechanisms rather than through ovulatory dysfunction alone.
Inflammation and Oxidative Stress
The 2026 review also discusses chronic low-grade inflammation as an important feature of PMOS.
Studies have identified elevations in inflammatory markers such as C-reactive protein, tumor necrosis factor (TNF), and interleukin-6 (IL-6) in some affected populations.
Inflammatory signaling can interact with insulin sensitivity, adipose tissue function, and reproductive physiology.
However, inflammation is not universally elevated in every individual with PMOS, and these biomarkers are not diagnostic tests for the condition.
The clinical significance lies in understanding how metabolic, endocrine, and inflammatory processes may reinforce one another.
Why Pregnancy Places Additional Demands on Metabolic Health
Pregnancy is a remarkable example of human physiological adaptation.
Throughout gestation, the maternal body undergoes coordinated changes in endocrine function, glucose metabolism, blood circulation, immune regulation, and nutrient allocation.
These adaptations support fetal development while maintaining maternal health.
During early pregnancy, the body undergoes changes that favor energy storage and support placental development.
As pregnancy progresses, insulin sensitivity normally declines, helping make nutrients available to the developing fetus.
Hormones and inflammatory mediators, including placental lactogen, cortisol, and TNF, participate in these metabolic adaptations.
In an uncomplicated pregnancy, these changes are generally supported by appropriate pancreatic insulin secretion and metabolic regulation.
However, women entering pregnancy with substantial insulin resistance may have less capacity to accommodate the additional metabolic demands.
For women with PMOS, pre-existing insulin resistance, hyperandrogenism, inflammatory activity, or other metabolic abnormalities may interact with normal pregnancy physiology in ways that increase the risk of complications.
Pregnancy does not create every underlying metabolic vulnerability. In some cases, it reveals or amplifies vulnerabilities that were already present before conception.
This is one reason preconception health deserves greater attention.
PMOS and Pregnancy Complications: What Does the Research Show?
The 2026 Nature Reviews Endocrinology review summarizes extensive evidence linking PMOS with increased risks of several pregnancy and birth complications.
Importantly, many of these associations remain significant after accounting for age and BMI.
A 2024 systematic review and meta-analysis published in Nature Communications evaluated 104 studies involving 106,690 pregnancies.
Researchers found that women with PCOS experienced higher rates of miscarriage, gestational diabetes, gestational hypertension, preeclampsia, and cesarean delivery.
The 2026 review provides further context for these findings.
Gestational Diabetes Mellitus
Gestational diabetes occurs when glucose regulation becomes insufficient to meet the metabolic demands of pregnancy.
Women with PMOS have an increased risk, partly because insulin resistance and compensatory hyperinsulinemia are common features of the condition.
The meta-analysis summarized in the 2026 review found approximately 2.4 times the odds of gestational diabetes among women with PMOS compared with unaffected women.
This association remained significant in analyses accounting for age and BMI.
Gestational Hypertension and Preeclampsia
Pregnancy-related hypertensive disorders are another major concern.
Gestational hypertension involves elevated blood pressure developing during pregnancy, while preeclampsia is a more complex condition involving hypertension and additional evidence of maternal organ dysfunction or other clinical abnormalities.
The reviewed research identified approximately 2.2 times the odds of gestational hypertension and 2.3 times the odds of preeclampsia among women with PMOS.
Proposed contributing mechanisms include impaired vascular regulation, insulin resistance, inflammatory signaling, and abnormal placental development.
Miscarriage and Early Pregnancy Loss
PMOS is also associated with an increased risk of miscarriage.
The 2026 review reported approximately 1.5 times the odds of miscarriage compared with women without PMOS.
Potential contributors include disturbances in ovulation, endometrial receptivity, metabolic regulation, and other reproductive factors.
However, the precise causes of individual miscarriages are often multifactorial and cannot be attributed to PMOS alone.
Preterm Birth and Fetal Growth
Research also identifies increased risks of preterm delivery, fetal growth restriction, and low birth weight.
The mechanisms remain incompletely understood, but placental function, maternal metabolic health, and inflammatory pathways are important areas of investigation.
These associations do not mean that complications are inevitable. Many women with PMOS experience healthy pregnancies and deliveries.
Rather, the findings demonstrate why PMOS should be recognized as a clinically meaningful pregnancy risk factor that warrants appropriate screening and individualized prenatal care.
The Placenta: An Important Connection Between Maternal and Fetal Health
One of the most compelling aspects of the research involves placental physiology.
The placenta serves as a critical interface between maternal and fetal systems, supporting nutrient transfer, gas exchange, endocrine signaling, and immune regulation.
Successful pregnancy requires appropriate placental development and adaptation.
The 2026 review discusses evidence suggesting that hyperandrogenism, insulin resistance, inflammatory dysregulation, and altered endometrial signaling may influence implantation and placental development.
For example, disturbances in androgen signaling and vascular remodeling may affect the development of placental blood vessels.
Similarly, metabolic dysfunction may influence lipid handling, oxidative stress, and placental nutrient transport.
These mechanisms offer possible explanations for why PMOS is associated with both maternal complications and altered fetal growth.
However, many detailed molecular pathways remain under investigation.
The evidence is strongest for the association between PMOS and pregnancy complications; the precise contribution of each proposed mechanism is not yet fully established.
Why Fertility Treatment Alone May Not Address the Full Problem
Many women with PMOS seek fertility treatment because of irregular ovulation or difficulty conceiving.
Ovulation induction can be an effective medical strategy for addressing anovulatory infertility, and many affected women conceive naturally or with appropriate treatment.
However, achieving ovulation or conception does not automatically eliminate underlying metabolic risk.
For example, a woman may successfully conceive following ovulation induction while continuing to experience insulin resistance or other cardiometabolic concerns.
These factors may remain relevant during pregnancy.
The 2026 review also discusses how assisted reproductive technologies can introduce additional considerations, particularly when maternal metabolic risk factors coexist.
The purpose of comprehensive care is not to replace effective fertility treatment.
It is to recognize that fertility outcomes and pregnancy health are related but distinct clinical goals.
Supporting ovulation addresses one important component of reproductive health. Preconception assessment also considers the broader physiological conditions in which pregnancy will occur.
The Importance of Preconception Health
Preconception care refers to assessment and interventions intended to improve health before pregnancy.
For women with PMOS, this period offers a valuable opportunity to identify and manage factors that may influence fertility, pregnancy, and long-term well-being.
The 2023 International Evidence-Based Guideline for PCOS, reinforced by the 2026 review, emphasizes screening for reproductive, metabolic, cardiovascular, and psychological concerns before conception.
Relevant considerations include glucose regulation, blood pressure, nutritional status, physical activity, sleep, medications, and mental health.
The guideline recommends an oral glucose tolerance test when planning pregnancy in women with PMOS because of their increased risk of glucose intolerance and gestational diabetes.
Nutrition and Metabolic Health
A comprehensive nutritional assessment may help identify opportunities to improve dietary quality, nutrient adequacy, and metabolic health.
For example, nutrition interventions may emphasize adequate protein, dietary fiber, nutrient-dense foods, appropriate energy intake, and sustainable eating patterns.
Recommendations should be individualized according to metabolic status, personal preferences, current health conditions, and pregnancy intentions.
There is no single dietary pattern that has been established as universally superior for all women with PMOS.
Appropriate nutritional care should therefore prioritize sustainable improvements rather than rigid dietary rules.
Physical Activity and Exercise
Regular physical activity can support insulin sensitivity, cardiovascular health, body composition, and psychological well-being.
Resistance training and aerobic exercise may both contribute to improved metabolic regulation.
However, exercise prescription should account for individual fitness, medical conditions, recovery capacity, and nutritional adequacy.
The goal is not simply to increase exercise volume, but to improve physiological capacity through appropriately matched activity.
Sleep and Psychological Well-Being
Sleep disturbances, anxiety, depression, and other psychosocial concerns are important considerations in PMOS.
These factors can influence health-related behaviors, quality of life, and metabolic regulation.
Addressing them may improve overall well-being and help women participate more effectively in their care.
Psychological health screening is also recommended as part of comprehensive PMOS management.
Weight Management When Appropriate
For some individuals, reducing excess adiposity can improve metabolic health and reproductive function.
However, PMOS occurs across the body-weight spectrum.
Weight loss should not be treated as the universal solution, nor should a normal BMI be assumed to exclude metabolic dysfunction.
Clinical priorities should be based on the individual's actual risk factors, health needs, and pregnancy goals.
What About Metformin and Nutritional Supplements?
Because insulin resistance is common in PMOS, medications and nutritional supplements intended to improve metabolic function receive considerable attention.
Metformin is one medication used in selected women with PCOS to address metabolic concerns and, in some circumstances, reproductive outcomes.
However, its role differs before and during pregnancy.
The 2026 review emphasizes that metformin should not be routinely prescribed during pregnancy solely to prevent complications associated with PMOS.
Although some studies suggest benefits for gestational weight gain or preterm birth, available evidence does not establish consistent prevention of gestational diabetes, miscarriage, or preeclampsia.
Likewise, supplements such as myo-inositol have been investigated for reproductive and metabolic outcomes.
The review notes that evidence has not established improved pregnancy or live birth rates from inositol supplementation in this population.
This distinction is important because biological plausibility does not automatically establish clinical effectiveness.
The value of an intervention should be judged by meaningful outcomes, safety, and evidence—not simply by whether it influences a hormone or laboratory biomarker.
Medication and supplementation decisions should be made with the patient's qualified reproductive or prenatal healthcare team.
Does PMOS Affect the Long-Term Health of Children?
Research increasingly investigates whether maternal PMOS is associated with health outcomes extending beyond pregnancy and delivery.
The 2026 review discusses observational associations involving offspring metabolic health, growth patterns, and certain neurodevelopmental and psychological outcomes.
Potential mechanisms include genetic susceptibility, maternal metabolic conditions, placental function, and the intrauterine environment.
However, these relationships are complex.
Factors such as maternal BMI, gestational diabetes, pregnancy complications, genetics, and environmental circumstances may contribute independently or interact.
Consequently, current research does not establish that PMOS directly causes specific long-term conditions in offspring.
Nor does it demonstrate that a particular preconception intervention can reliably prevent these outcomes.
The evidence instead reinforces the importance of continued research and appropriate maternal health support before, during, and after pregnancy.
Why Precision Healthcare Matters in PMOS
One challenge in managing PMOS is that individuals can have very different clinical presentations.
Some women primarily experience irregular menstrual cycles and infertility.
Others have prominent hyperandrogenic symptoms.
Some experience significant metabolic dysfunction, while others have relatively favorable metabolic measurements.
These differences help explain why the same treatment strategy does not produce identical results for every patient.
A 2026 review in Nature Metabolism, Metabolic Homeostasis and Women's Reproductive Health, emphasizes the dynamic, bidirectional relationships among metabolic organs, endocrine signaling, and female reproductive physiology.
Similarly, emerging genetic research has identified numerous genetic variants associated with reproductive and metabolic features of PMOS, further illustrating its biological complexity.
These discoveries support the development of more precise approaches to assessment and management.
However, precision healthcare does not require every individual to undergo extensive genomic, microbiome, or specialty hormone testing.
The most useful strategy begins with validated clinical assessments and then incorporates additional information when it can meaningfully improve clinical decisions.
For women with PMOS, this means recognizing the individual combination of reproductive, metabolic, psychological, and cardiovascular factors influencing health.
Our Approach to Women's Health and Conscious Conception
Our women's health philosophy recognizes that fertility and reproductive function are interconnected with broader physiological health.
Rather than viewing ovulation, menstrual symptoms, metabolism, nutrition, stress, and cardiovascular health as unrelated concerns, we seek to understand how these factors interact within the individual.
Our approach to women's wellness and preconception coaching emphasizes education, individualized assessment, and the development of sustainable health behaviors.
Depending on the patient, this may involve reviewing menstrual history, dietary intake, physical activity, sleep quality, stress burden, metabolic risk factors, and relevant medical history.
For women with PMOS, these findings may provide important context for understanding the interaction between reproductive symptoms and metabolic health.
When appropriate, we encourage targeted laboratory evaluation and collaboration with obstetricians, gynecologists, reproductive endocrinologists, primary care clinicians, and other qualified healthcare professionals.
Our role is not to replace fertility treatment or obstetric management.
Instead, we aim to complement appropriate medical care through evidence-informed lifestyle support, patient education, and individualized health coaching.
The objective is to help women become more informed and active participants in their health decisions while supporting the physiological foundations of pregnancy and long-term wellness.
Moving Beyond Conception Toward Comprehensive Maternal Health
The research surrounding PMOS illustrates an important evolution in women's healthcare.
Reproductive health cannot be fully understood without considering the metabolic, endocrine, inflammatory, and cardiovascular processes that support it.
Likewise, a successful conception does not eliminate the importance of maternal health throughout pregnancy.
The 2026 Nature Reviews Endocrinology review reinforces the need to recognize PMOS as a meaningful risk factor for pregnancy complications and to improve preventive care before and during pregnancy.
Its findings also highlight the value of looking beyond isolated symptoms toward understanding the interacting systems that influence reproductive and maternal health.
This perspective is particularly relevant to women preparing for pregnancy, where early identification of modifiable risk factors may create opportunities for more informed and coordinated care.
The goal of preconception healthcare should not simply be to achieve pregnancy. It should also be to support the health of the individual entering pregnancy, recognize potential risks early, and establish the strongest evidence-informed foundation possible for maternal and child well-being.
We believe that meaningful women's healthcare begins with understanding these relationships—and empowering women with the knowledge, resources, and personalized support necessary to make informed decisions throughout their reproductive lives and beyond.
Research References
Teede HJ, Vanky E, Piltonen TT, Stener-Victorin E, Moran LJ, Bahri Khomami M. Polyendocrine metabolic ovarian syndrome in pregnancy: pathophysiology and outcomes. Nature Reviews Endocrinology. 2026;22:516–529. https://doi.org/10.1038/s41574-026-01261-w
Bahri Khomami M, Shorakae S, Hashemi S, et al. Systematic review and meta-analysis of pregnancy outcomes in women with polycystic ovary syndrome. Nature Communications. 2024;15:5591. https://doi.org/10.1038/s41467-024-49749-1
Helvaci N, Yildiz BO. Polycystic ovary syndrome as a metabolic disease. Nature Reviews Endocrinology. 2025;21:230–244. https://doi.org/10.1038/s41574-024-01057-w
Kordowitzki P, Teede H. Polyendocrine metabolic ovarian syndrome—a new name for an old problem. Nature Metabolism. 2026;8:1443–1445. https://doi.org/10.1038/s42255-026-01552-6
Liu X, Yang L, Jiang J, et al. Metabolic homeostasis and women's reproductive health. Nature Metabolism. Published October 15, 2026. https://doi.org/10.1038/s42255-026-01646-1
Genomic analyses implicate hormonal and metabolic dysregulation in polycystic ovary syndrome. Nature Genetics. 2026;58:1040–1050. https://doi.org/10.1038/s41588-026-02543-9
Moran LJ. Advances in cardiometabolic outcomes in polycystic ovary syndrome. Nature Reviews Endocrinology. 2025;21:67–68. https://doi.org/10.1038/s41574-024-01072-x
Teede HJ, et al. (2026). Polyendocrine metabolic ovarian syndrome, the new name for polycystic ovary syndrome: a multistep global consensus process. The Lancet. Published May 12, 2026.
Teede HJ, Tay CT, Laven JJE, et al. Recommendations from the 2023 international evidence-based guideline for the assessment and management of polycystic ovary syndrome. Fertility and Sterility. 2023;120:767–793.
Khan SS, Grobman WA, Perak AM, et al. A female-specific life course approach to the prevention and management of cardiovascular disease. Circulation. 2026. https://doi.org/10.1161/CIR.0000000000001483