Clear, evidence-based guides on PCOS, periods, skin, weight, mood and more. Written by our doctor, with every fact linked to its source.
Periods
Why PCOS makes periods late or stop, the exact cycle lengths that count as irregular, when a long gap becomes a risk, and what actually helps.
By Dr. Parikshit · 10 min read
Weight & metabolism
Why PCOS makes weight gather around the middle and resist dieting, what a 5-10% loss really does, the diabetes numbers, and a plan that fits Indian food.
By Dr. Parikshit · 10 min read
Mood, sleep & energy
Why anxiety, low mood and mood swings are so common in PCOS, the warning signs that need help today, and what actually helps.
By Dr. Parikshit · 9 min read
Weight & metabolism
Why PCOS disturbs sleep, how common sleep apnoea really is, the signs to watch for, and how better sleep helps insulin resistance.
By Dr. Parikshit · 8 min read
Periods
PCOS is linked to pain and bloating, but the cysts are rarely the cause - here is what to check, and when pain is an emergency.
By Dr. Parikshit · 9 min read
Skin & hair
That dark, velvety neck patch is a visible sign of high insulin - here is what it means, which tests to get, and how it fades.
By Dr. Parikshit · 9 min read
Weight & metabolism
Why PCOS leaves so many women exhausted, the five hidden causes worth testing for, and what actually brings your energy back.
By Dr. Parikshit · 9 min read
PCOS basics
An honest look at PCOS and brain fog: what studies show about memory and focus, what is still unknown, and the testable causes worth fixing first.
By Dr. Parikshit · 9 min read
Skin & hair
Why PCOS thins scalp hair, which other causes to rule out first, the tests to ask for, and which treatments actually regrow hair.
By Dr. Parikshit · 9 min read
Skin & hair
Why PCOS causes coarse facial and body hair, how it is scored for Indian women, which tests to get, and which treatments work over what timeline.
By Dr. Parikshit · 9 min read
Tests
Understand PCOS in Young Women: symptoms, teen diagnosis rules, key tests, and care options for 2026. Learn the next steps.
By Dr. Parikshit · 17 min read
Periods
Polycystic ovaries pregnancy explained: fertility, risks, and treatments. Learn how to confirm ovulation, use letrozole,
By Dr. Parikshit · 16 min read
Periods
Androgen hormones support bone, muscle, and fertility; excess can cause hirsutism, acne, and irregular periods. Learn ke
By Dr. Parikshit · 16 min read
Skin & hair
PCOS face hair (hirsutism) explained: why it happens and what truly helps-medical care plus removal. See options, timeli
By Dr. Parikshit · 20 min read
PCOS basics
Wondering what is a good AMH level to get pregnant? See the 1-4 ng/mL range, why age and ovulation matter most, and how
By Dr. Parikshit · 17 min read
Periods
Polycystic ovaries on a scan are not a diagnosis - and not a barrier to pregnancy.
By Dr. Parikshit · 10 min read
Periods
Adult hormonal acne settles on the lower face - and tracks your cycle.
By Dr. Riya · 6 min read
PCOS basics
Yes. And here is what that actually means for your body.
By Dr. Riya · 5 min read
PCOS basics
A normal weight is not a clearance. It is one of the most missed presentations.
By Dr. Parikshit · 6 min read
PCOS basics
PCOS is not one condition. It is at least four distinct presentations.
By Dr. Parikshit · 6 min read
Weight & metabolism
Your blood sugar can read normal for years while your insulin quietly climbs.
By Dr. Parikshit · 6 min read
PCOS basics
PCOS is rarely one loud symptom. It is usually several quiet ones.
By Dr. Parikshit · 5 min read
Skin & hair
What skin tags are, why they are linked with diabetes and insulin resistance, how they differ from dark neck patches, and when they are worth showing a doctor.
By Dr. Parikshit · 8 min read
PCOS basics
How the international guideline describes polycystic ovaries, why the round shapes are follicles, how many follicles count, what a good scan report includes, and why a scan alone does not diagnose PCOS.
By Dr. Akash Mehra · 9 min read
Weight & metabolism
How much activity the international PCOS guideline advises, why no single type of exercise wins, how exercise links with insulin resistance, and why sitting less matters even when weight does not change.
By Dr. Akash Mehra · 9 min read
PCOS basics
The three features doctors look for, why two are enough, when an ultrasound or AMH test is needed, how the rules differ for teenagers, and what the new name PMOS changes.
By Dr. Parikshit · 10 min read
Periods
What counts as an irregular cycle, what to write down each month, how to describe heavy bleeding, how far to trust a period app, and what to take to your gynaecologist.
By Dr. Parikshit · 9 min read
These articles are general health education, written by our doctor. They are not a diagnosis. For advice about your own body, book a PCOS Assessment.
Quick answer
The Rotterdam criteria are the rules doctors use to diagnose PCOS. Two of three features are needed: irregular or absent ovulation, signs or blood tests showing high androgens, and polycystic ovaries on an ultrasound or a raised AMH level. Other causes are ruled out first, and ovarian cysts are not required.
Tvarvi Key Takeaways
What the criteria ask for
- Two of three features are enough for a diagnosis.
- By these rules, 10% to 13% of women worldwide have PCOS.
- Conditions with similar signs are ruled out first.
Tests a doctor may use
- A blood test can show high androgen levels.
- Adults may have an ultrasound or an AMH test, not both.
- Neither is needed when cycles and androgens already point to PCOS.
Teenagers and the new name
- Teenagers need both irregular cycles and high androgens.
- Ultrasound and AMH are not recommended for teenagers.
- The new name PMOS keeps the same diagnostic rules.
In this article
The Rotterdam criteria are a checklist of three features, and a doctor diagnoses PCOS when at least two are present and other causes have been excluded. They come from a 2003 consensus workshop in Rotterdam sponsored by the European and American reproductive medicine societies, which concluded that no single sign, such as high androgens or polycystic ovaries, is enough on its own for a diagnosis.
The 2023 International Evidence-based Guideline still builds on this framework. It asks for two of the following: high androgens shown by signs or blood tests, ovulatory dysfunction (ovulation that is irregular or absent), and polycystic ovaries on ultrasound, and since 2023 it accepts an anti-Müllerian hormone (AMH) blood test in place of the ultrasound.
The WHO fact sheet on PCOS describes the same rule and adds that ovarian cysts are not required for a PCOS diagnosis. For the bigger picture of what PCOD and PCOS are, read our main guide, What is PCOD?
Table 1. The three Rotterdam features and how a doctor may check them
| Feature | What it means | How a doctor may check |
|---|---|---|
| Ovulatory dysfunction | Ovulation is irregular or absent | Cycle history, and a progesterone test if cycles seem on time |
| High androgens | Signs such as excess facial or body hair, or high levels in a blood test | Examination, and total and free testosterone |
| Polycystic ovarian morphology | Many follicles in an ovary, or a larger ovary | A pelvic ultrasound in adults, or an AMH blood test instead |
Source: Teede et al., Recommendations from the 2023 International Evidence-based Guideline for the Assessment and Management of PCOS, J Clin Endocrinol Metab, 2023. Alt text: "Table listing the three Rotterdam features of PCOS and how a doctor may check each one."
The 2023 guideline says PCOS shows up in different ways in different women (it calls the presentation heterogeneous), so the criteria accept any two of the three features instead of one fixed pattern. The Rotterdam workshop noted that, since a 1990 conference of the US National Institutes of Health (NIH), the condition had come to be seen as covering a broader range of ovarian dysfunction than the original criteria described.
Other definitions exist: the Androgen Excess Society's 2006 position statement concluded that PCOS should first be considered a disorder of androgen excess, and recommended the NIH criteria with some modifications.
The set of rules used changes how common PCOS looks. The ICMR-funded nationwide study by Ganie and colleagues (JAMA Network Open, 2024), which assessed 8,993 women aged 18 to 40 across five zones of India, found a prevalence of 7.2% with the NIH 1990 criteria, 19.6% with the Rotterdam criteria and 13.6% with the Androgen Excess and PCOS Society criteria.
Worldwide, the 2023 guideline puts prevalence at 10% to 13% using the Rotterdam criteria.
Irregular periods are one sign of ovulatory dysfunction, and the guideline gives exact cycle lengths. From three years after the first period until perimenopause, the 2023 guideline defines cycles as irregular when they are shorter than 21 days, longer than 35 days, or fewer than 8 a year.
The same recommendation covers the earlier years. Cycles that vary are normal in the first year after the first period; between one and three years after it, cycles under 21 days or over 45 days count as irregular; and any single cycle longer than 90 days counts once a year has passed since the first period (Teede et al., 2023).
Ovulation can also be disrupted when periods arrive on time. In that case, the guideline notes that a doctor can measure progesterone in the blood to confirm whether ovulation is happening. Read more in Can you have PCOS if your periods come on time?
Androgens are hormones such as testosterone, and doctors look for them in two ways: signs on the body and a blood test. The 2023 guideline recommends total and free testosterone, with free testosterone estimated through the free androgen index, and if these are not raised, a doctor could consider androstenedione and DHEAS.
On the body, the guideline treats excess facial or body hair (hirsutism) on its own as predictive of high androgens and PCOS in adults. It also says acne or scalp hair thinning without excess hair are relatively weak predictors of high androgen levels.
Our page on PCOS blood tests explains what each test looks for and when a doctor may suggest it.
Not always. When irregular cycles and high androgens are both present, the 2023 guideline says an ultrasound or AMH test is not required for the diagnosis.
When one of those features is missing, adults may have a pelvic ultrasound. The guideline sets the threshold for polycystic ovarian morphology at 20 or more follicles in at least one ovary, and says an internal (transvaginal) scan gives the clearest count, but only if the woman is comfortable with it.
An abdominal scan can be used instead, for example for women who have not been sexually active. The StatPearls clinical reference on gynaecological sonography notes that abdominal ultrasound can be used for young women who have not been sexually active, and the 2023 guideline says an abdominal scan should mainly report ovary volume, with 10 mL or more in either ovary as the threshold.
An AMH blood test is now an alternative to the scan for adults. The guideline recommends that AMH should not be used as a single test for PCOS, and that either AMH or ultrasound may be used to look for polycystic ovaries, but not both, to limit over-diagnosis.
Other conditions can cause similar signs, so PCOS is diagnosed only once they have been excluded. The guideline's diagnostic algorithm lists thyroid function (TSH), prolactin, 17-hydroxyprogesterone and FSH, and other causes such as Cushing's syndrome or adrenal tumours when a doctor suspects them.
The timing of symptoms also matters. The guideline says the history of when symptoms began, and how quickly they progressed, is critical when a doctor assesses whether an androgen-secreting tumour needs to be ruled out.
The rules are stricter for teenagers. Diagnosis requires both irregular cycles and high androgens, and ultrasound and AMH tests are not recommended for adolescents because of their low specificity at this age, as the 2023 guideline explains.
For a teenager who has some features but does not meet the criteria, the guideline suggests an "increased risk" label could be considered, with a reassessment at or before 8 years after the first period. It also advises that the timing of assessment is discussed with the young person and their parents or guardians.
If you are a teenager with these questions, it helps to see a gynaecologist with a parent or guardian.
No. In 2026, a global consensus published in The Lancet renamed PCOS polyendocrine metabolic ovarian syndrome (PMOS), partly because the old name implies pathological ovarian cysts.
A 2026 report for obstetricians and gynaecologists in the American Journal of Obstetrics and Gynecology states that the diagnostic criteria remain unchanged. Two of these three are needed, as in the 2023 guideline:
More on the rename in PCOS has a new name: PMOS.
If your periods are irregular or you have noticed signs such as extra facial hair, a gynaecologist can talk you through the tests that fit your situation.
Can you have PCOS with a normal ultrasound? Yes. The WHO PCOS fact sheet notes that some women with PCOS do not have polycystic ovaries, because the other two features are enough for a diagnosis.
Do I need both an ultrasound and an AMH test? No. The 2023 guideline advises that adults have one or the other, not both, to limit over-diagnosis.
Does a PCOS diagnosis last for life? The 2023 guideline says a diagnosis of PCOS could be considered enduring or lifelong. The WHO adds that treatments can improve quality of life.
How many women have PCOS without knowing it? The WHO estimates that PCOS affects 10 to 13% of women of reproductive age, and that up to 70% of women with PCOS worldwide do not know they have it.
This article is general health information and does not replace a consultation about your own health. Medical decisions depend on your individual situation and should be made with a registered doctor. If you are struggling with your mood, Tele MANAS (14416) is free and open all day.
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