Published: 24 September 2026
Medically reviewed by Dr. Pranay Shah, MS (Obs. & Gyn.), Director & Chief Fertility Consultant, Wellspring IVF & Women’s Hospital, Ahmedabad
Last medically reviewed: 24 September 2026
PCOS diagnosis criteria for adults follow the Rotterdam rule: two of three features must be present, namely irregular or absent ovulation, clinical or biochemical excess of androgens, and polycystic ovarian morphology on ultrasound. Since the 2023 international guideline, a raised anti-Müllerian hormone (AMH) level can stand in for the ultrasound. Other conditions that mimic PCOS have to be excluded first. Because only two of the three are needed, an ultrasound is not always necessary, and a scan alone can never make the diagnosis.
That last point causes more confusion in clinic than any other. Many women arrive with a scan report that says “polycystic ovaries” and assume the question is settled. It is open in both directions. Some of them do not have PCOS, and others have PCOS with ovaries that look entirely normal. Here is what each of the three criteria requires, what the international guideline has changed, and what a complete work-up should include.
First, a name change you will start to see: PCOS is now also called PMOS
In May 2026 the international guideline group renamed the condition. Polycystic ovary syndrome (PCOS) is now formally polyendocrine metabolic ovarian syndrome (PMOS), and the International Evidence-based Guideline was updated in June 2026 to reflect this. The guideline describes a managed transition in which both terms appear together as “PMOS/PCOS” for about three years, with the new name used alone from the next full update. Major professional bodies, including the American Society for Reproductive Medicine, have adopted the new terminology in their practice guidance.
The old name pointed to an ovarian imaging finding that is neither necessary for diagnosis nor the core of the problem, since the condition is an endocrine and metabolic disorder. Nothing about diagnosis or management changes for patients. This article keeps the term PCOS because it is what you will hear in Indian clinics and see on your reports, though you may meet “PMOS” on newer documents.
What are the Rotterdam criteria?
The Rotterdam criteria are a rule for combining findings, and no single test stands behind them. In an adult woman, PCOS is diagnosed when any two of these three are present and other causes have been excluded.
# | Criterion | What it means in practice |
1 | Ovulatory dysfunction | Irregular, infrequent or absent menstrual cycles, judged against the woman’s gynaecological age (years since her first period) |
2 | Hyperandrogenism | Either clinical signs of androgen excess such as hirsutism, or a raised total or calculated free testosterone on a reliable assay |
3 | Polycystic ovarian morphology, or raised AMH | Follicle number per ovary of 20 or more in at least one ovary on ultrasound — or, in adults, an elevated serum AMH used as an alternative to the scan |
Adapted from the 2023 International Evidence-based Guideline, as updated in 2026. Two of three are required in adults.
Two consequences follow straight away. A woman with irregular cycles and demonstrable hyperandrogenism already meets the criteria, and an ultrasound adds nothing to the diagnosis. And polycystic-looking ovaries on their own are one criterion out of three, a finding that is also common in women who do not have the syndrome at all.
Criterion 1: what counts as an irregular cycle?
The guideline defines this precisely, and the definition depends on how long ago you started menstruating and not on your age in years.
Time since first period (gynaecological age) | Cycle pattern considered irregular |
First year after menarche | Irregularity is normal at this stage and is part of the pubertal transition |
More than 1 year and less than 3 years after menarche | Cycles shorter than 21 days or longer than 45 days |
More than 3 years after menarche, up to perimenopause | Cycles shorter than 21 days, longer than 35 days, or fewer than 8 cycles in a year |
More than 1 year after menarche | Any single cycle longer than 90 days |
Source: 2023 International Evidence-based Guideline, recommendation 1.1.1.
Check your own record against this table before an appointment, because “irregular” is used loosely in everyday talk. A woman with a steady 33-day cycle does not have ovulatory dysfunction by these criteria, however irregular it feels next to a friend’s 28-day cycle. Equally, eight or fewer periods in a year meets the definition even if each one arrives on schedule.
Criterion 2: how is androgen excess established?
Either clinically or biochemically. Both routes are acceptable and one is enough.
Clinical hyperandrogenism
The guideline says hirsutism alone should be taken as predictive of biochemical androgen excess, and it recommends a modified Ferriman-Gallwey score of 4 to 6 as the threshold for detecting hirsutism. Acne and androgenic hair loss are recognised too but are weaker and less specific signs. A structured examination matters here. Hirsutism is often under-recorded, particularly where cosmetic hair removal is routine, so tell your clinician what you already do about it.
Biochemical hyperandrogenism
The guideline recommends measuring total and free testosterone, with free testosterone estimated through the calculated free androgen index. It also makes a point that practice often overlooks: laboratories should use validated, highly accurate assays, meaning liquid chromatography-tandem mass spectrometry (LC-MS/MS), because the direct immunoassays widely used for free testosterone are unreliable at the concentrations found in women. If your report gives a directly measured “free testosterone” from an immunoassay, treat the number with caution.
One more practical point: androgen levels are suppressed if you are taking, or have recently stopped, a combined hormonal contraceptive, and they cannot be interpreted. A washout period is usually needed before testing.
Criterion 3: ultrasound or AMH
Do you need an ultrasound to diagnose PCOS?
Not always. When an adult has both irregular cycles and hyperandrogenism, the diagnosis is already made and imaging is not required. Where an ultrasound is indicated and the woman agrees, the transvaginal approach is the most accurate for judging ovarian morphology.
The threshold is a follicle number per ovary of 20 or more in at least one ovary. If image quality or equipment does not allow a reliable follicle count, the guideline accepts an ovarian volume of 10 mL or more, or a follicle number per cross-section of 10 or more, in at least one ovary. This causes much confusion in India, where older reports were often issued against a threshold of 12 follicles. A scan called polycystic under the older count may not meet the current definition.
Can AMH be used to diagnose PCOS?
Serum AMH can now be used to define polycystic ovarian morphology in adults as an alternative to ultrasound, which was the biggest change introduced by the 2023 guideline. Two limits matter just as much. AMH should not be used as a single test to diagnose PCOS, because it replaces one of the three criteria and cannot replace the whole rule. And it is not recommended in adolescents.
There is also no internationally agreed AMH cut-off. Values differ a good deal between assay platforms and between reference populations, so a threshold means something only in relation to the assay and population it came from. An AMH figure quoted without its assay cannot be interpreted, and a high AMH in a woman with regular ovulatory cycles and no androgen excess does not add up to PCOS.
What has to be ruled out before PCOS is diagnosed?
PCOS is a diagnosis of exclusion in the sense that several other conditions produce a similar picture and must be considered first. In routine assessment the guideline names the following.
Test | Condition it excludes | Why it matters |
Thyroid stimulating hormone (TSH) | Thyroid dysfunction | Thyroid disease commonly disturbs cycles and is treated quite differently |
Prolactin | Hyperprolactinaemia | Raised prolactin suppresses ovulation and may indicate a pituitary cause |
17-hydroxyprogesterone | Non-classic congenital adrenal hyperplasia | Mimics PCOS closely with hyperandrogenism and irregular cycles; genetic counselling implications differ |
Further testing, for example for Cushing’s syndrome or an androgen-secreting tumour, is indicated only when the clinical picture suggests it, such as rapidly progressive virilisation.
Why adolescents are diagnosed differently
In adolescents the Rotterdam rule does not apply in its adult form. Both hyperandrogenism and ovulatory dysfunction are required, and ultrasound and AMH are not recommended for diagnosis within eight years of the first period. No definitive criteria exist for polycystic ovarian morphology on ultrasound in adolescents at all.
Multifollicular ovaries and irregular cycles are both normal in the years after menarche, so imaging at this age produces false positives and little clarity. When a young woman has features suggestive of PCOS but does not meet the full criteria, the guideline puts her in an “at increased risk” category with planned reassessment, rather than giving her a label that may follow her for life. If your daughter was given a PCOS diagnosis on the strength of a scan within a few years of her first period, it is reasonable to ask a specialist to revisit it.
Why the criteria used change the answer: the Indian data
How common PCOS appears to be depends heavily on which rule is applied, and the effect is large. A systematic review and meta-analysis of Indian studies (Bharali and colleagues, Cureus, 2022) pooled 11 studies and 6,555 women aged 10 to 45. It found a prevalence of 11.33% using the Rotterdam criteria (95% confidence interval 7.69 to 15.59), against 5.8% using the older NIH criteria and about 10% using the AES criteria.
Roughly twice as many Indian women meet the Rotterdam definition as meet the NIH one. Neither figure is wrong, since they answer different questions. If you have been told at different times that you do and do not have PCOS, the simplest explanation may be that two clinicians used two different rules. That is a reason to ask which criteria were applied, and no reason to assume either clinician was careless.
Internationally, the guideline puts prevalence at 10 to 13% and notes that it is broadly similar across world regions and ethnic groups, though it may be higher in South East Asian and Eastern Mediterranean populations and the way the condition presents can differ between groups.
Myths and what the evidence actually shows
Common claim | What the evidence shows |
“My scan shows polycystic ovaries, so I have PCOS.” | Polycystic ovarian morphology is one of three criteria and is common in women without the syndrome. It cannot make the diagnosis on its own. |
“My ovaries look normal, so I cannot have PCOS.” | If irregular cycles and hyperandrogenism are both present, the criteria are met without any imaging finding. |
“A high AMH means PCOS.” | AMH may substitute for the ultrasound criterion in adults, but is explicitly not to be used as a single diagnostic test, and there is no universal cut-off. |
“PCOS means I will need IVF.” | PCOS is a common and generally treatable cause of ovulatory infertility. Most women with PCOS who conceive do so with ovulation induction rather than IVF. |
“PCOS is only a fertility problem.” | It is an endocrine and metabolic condition with long-term implications beyond fertility, which is part of the reasoning behind the 2026 rename. |
“Cysts on the ovary need to be removed.” | The follicles counted in this diagnosis are not cysts in the surgical sense and are not an indication for surgery. |
When should you see a fertility specialist?
A structured assessment is reasonable in any of these situations, and the sooner the better if you are trying to conceive.
- Fewer than eight periods a year, or any cycle longer than 90 days, more than a year after your first period.
- Twelve months of unprotected intercourse without conception, or six months if you are 35 or older.
- A PCOS label given on a scan alone, with no assessment of cycles or androgens.
- Progressive hirsutism, or a rapid onset of androgenic features, which needs assessment for other causes.
- A diagnosis made in adolescence that was never reassessed in adulthood.
A first assessment for suspected PCOS should establish all three criteria properly: a structured cycle history, an examination and androgen profile, and imaging or AMH only where it will change the answer, alongside the exclusion tests above. PCOS is one of several conditions that present as irregular cycles and difficulty conceiving, so it is usually assessed within a broader look at the causes of female infertility and not on its own.
Once the diagnosis is secure, management is stepped and individualised, and for most women it starts well before assisted reproduction is considered. Our approach to PCOS treatment sets out that sequence. When IVF does become relevant, PCOS brings specific safety points in stimulation that are worth understanding beforehand, and we cover them in our guide to PCOS and fertility before starting IVF.
Frequently asked questions
How is PCOS officially diagnosed?
By the Rotterdam criteria: two of three features — ovulatory dysfunction, hyperandrogenism, and polycystic ovarian morphology on ultrasound or a raised AMH — after excluding thyroid disease, hyperprolactinaemia and non-classic congenital adrenal hyperplasia.
Is a blood test enough to diagnose PCOS?
No. No single blood test diagnoses PCOS. Bloods establish one criterion and exclude other conditions; the cycle history is indispensable.
Can PCOS be diagnosed if my periods are regular?
Yes, if hyperandrogenism and polycystic ovarian morphology or raised AMH are both present. Regular cycles do not exclude the diagnosis, though they generally indicate that ovulation is occurring.
Does the ultrasound have to be transvaginal?
Where a scan is indicated and acceptable to the woman, the transvaginal approach is the most accurate. Where it is not appropriate or not acceptable, ovarian volume of 10 mL or more may be used instead of a follicle count.
My old report says 12 follicles meant polycystic ovaries. Has that changed?
Yes. The current threshold is 20 or more follicles per ovary in at least one ovary, using appropriate imaging. A scan reported as polycystic against an older threshold should be interpreted against the current criteria.
Should I ask for my diagnosis to be reviewed?
It is reasonable to ask which criteria were applied and which conditions were excluded, particularly if the diagnosis was made on imaging alone, made during adolescence, or made while you were taking hormonal contraception.
The key point to take away
PCOS is a pattern and a scan cannot show it. It is established by combining a cycle history, an androgen assessment and, only when it will change the answer, an ultrasound or AMH, with a short list of mimicking conditions excluded first. A diagnosis built on any one of those alone is incomplete, and an incomplete diagnosis leads to the wrong treatment plan.
If you have been told you have PCOS and are unsure how that conclusion was reached, or you have irregular cycles and want a proper assessment before trying to conceive, you can discuss your individual situation with a fertility specialist at Wellspring IVF & Women’s Hospital on +91 9099946050, Monday to Saturday, 10:00 AM to 4:00 PM.
References
- Monash University / International PMOS (PCOS) Network. International Evidence-based Guideline for the Assessment and Management of Polyendocrine Metabolic Ovarian Syndrome (formerly PCOS) — guideline hub and 2026 terminology update. monash.edu
- International PMOS (PCOS) Network. Updated guideline document, 12 June 2026. monash.edu
- Teede HJ, Tay CT, Laven J, et al. Recommendations from the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. *Human Reproduction* 2023;38(9):1655–1679. academic.oup.com
- Teede HJ, Tay CT, Laven J, et al. Recommendations from the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. *Journal of Clinical Endocrinology & Metabolism* 2023;108(10):2447–2469. academic.oup.com
- American Society for Reproductive Medicine. Recommendations from the 2023 International Evidence-based Guideline for the Assessment and Management of Polyendocrine Metabolic Ovarian Syndrome — ASRM practice guidance. asrm.org
- Bharali MD, Rajendran R, Goswami J, Singal K, Rajendran V. Prevalence of Polycystic Ovarian Syndrome in India: A Systematic Review and Meta-Analysis. *Cureus* 2022;14:e32351. doi:10.7759/cureus.32351. pmc.ncbi.nlm.nih.gov
