Polycystic ovary syndrome affects roughly 1 in 10 women of childbearing age in the United States, making it one of the most common hormonal disorders among this group. That translates to between 5% and 10% of women ages 15 to 44, though the true number is likely higher because an estimated 70% of women with PCOS worldwide remain undiagnosed.
Why the Numbers Vary So Widely
If you’ve seen PCOS prevalence quoted anywhere from 5% to over 20%, you’re not misreading. The number depends heavily on which diagnostic criteria a doctor uses. There are three major sets of criteria, and they cast very different nets. The original NIH criteria from 1990 are the strictest, requiring both irregular periods and elevated androgen levels. The Rotterdam criteria, introduced in 2003 and now the most widely used internationally, are broader: a woman only needs two out of three features (irregular periods, elevated androgens, or a specific pattern of ovarian cysts on ultrasound). A third set from the Androgen Excess and PCOS Society falls somewhere in between.
In one comparative study, the same group of women yielded a PCOS diagnosis rate of about 23% under NIH criteria, 29% under the Androgen Excess Society criteria, and 63% under Rotterdam criteria. That nearly threefold difference from the same patients illustrates why prevalence estimates swing so dramatically depending on which standard a healthcare system or study adopts. The commonly cited 5% to 10% figure from U.S. government sources reflects older, more conservative criteria. When Rotterdam criteria are applied to population-level data, global estimates climb to 10% to 13%.
Prevalence by Race and Ethnicity
PCOS does not affect all groups equally. A large observational study of U.S. health plan members in 2016, published in Fertility and Sterility, found notable differences in diagnosed PCOS rates across racial and ethnic groups. South Asian women had the highest diagnosed prevalence at 3.5%, more than double the 1.6% rate among white women. Hispanic women were diagnosed at 1.9%, Black women at 1.7%, and Filipino women also at 1.7%. Chinese women had the lowest rate at 1.1%.
These numbers reflect diagnosed cases only, which means they capture both biological differences and differences in healthcare access, diagnostic practices, and the likelihood of seeking care for symptoms like irregular periods or excess hair growth. The gap between the overall estimated prevalence (5% to 10%) and these diagnosed rates (all under 4%) reinforces just how many cases go unrecognized in every demographic group.
Rates Are Rising in Younger Women
The incidence of PCOS in the U.S. appears to be shifting toward younger age groups. Among women ages 16 to 20, the incidence rose from about 31 to 52 cases per 10,000 person-years compared to earlier estimates. At the same time, rates among women ages 26 to 30 dropped from 83 to 45 per 10,000 person-years. Researchers point to two likely explanations: the obesity epidemic may be triggering earlier onset of the condition, and growing awareness among healthcare providers means younger women are getting diagnosed sooner rather than waiting years for answers.
Overall U.S. incidence sits around 42.5 cases per 10,000 person-years, a rate that is many times higher than what’s been recorded in the United Kingdom. Whether that reflects a genuinely higher burden of disease in the U.S. or differences in how aggressively doctors screen for PCOS remains an open question.
The Health Risks That Come With It
PCOS is far more than a reproductive issue. The hormonal and metabolic disruptions it causes ripple across multiple body systems over a lifetime. The most striking statistic: more than half of women with PCOS develop type 2 diabetes by age 40, according to the CDC. That risk exists even in women who are not overweight, though excess weight amplifies it considerably.
PCOS is also one of the leading causes of difficulty getting pregnant. The condition disrupts ovulation, meaning eggs aren’t released on a regular schedule or sometimes not at all. Beyond fertility and diabetes, women with PCOS face elevated risks for gestational diabetes, preeclampsia, stroke, and cardiovascular disease over the long term.
The Cost of PCOS in the U.S.
Diagnosing and treating PCOS cost an estimated $8 billion in the United States in 2020 alone. That figure, reported by the Endocrine Society, breaks down in a revealing way. The initial diagnostic process accounted for less than 2% of the total. Pregnancy-related complications like gestational diabetes and preeclampsia made up about 5%. The overwhelming majority of costs, roughly $4.3 billion, went toward managing the long-term metabolic consequences: diabetes, cardiovascular problems, and related conditions that accumulate over years and decades.
This cost structure highlights a pattern that matters for anyone with PCOS. The condition itself is relatively inexpensive to identify. What becomes costly, both financially and in terms of health, is leaving it unmanaged. Early identification and consistent metabolic monitoring can reduce the downstream burden significantly.
Most Cases Still Go Undiagnosed
Perhaps the most important number in all of this: up to 70% of women with PCOS don’t know they have it. That means for every woman who has received a diagnosis, roughly two others are living with the same condition without a name for it. Some have been told their irregular periods are “just stress.” Others have symptoms like acne, thinning hair, or difficulty losing weight that they’ve never connected to a single underlying cause.
Part of the diagnostic gap comes from the condition’s variability. Not every woman with PCOS has cysts visible on an ultrasound. Not every woman has the same combination of symptoms. And because PCOS spans gynecology, endocrinology, and dermatology, no single specialty consistently “owns” the diagnosis. Women often visit multiple doctors over several years before someone puts the pieces together. If the U.S. prevalence is truly around 6 to 10 million women of reproductive age, that means several million are currently undiagnosed and missing the window for early intervention that could reduce their risk of diabetes and other complications later in life.