PCOD, the common Indian name for polycystic ovary syndrome (PCOS), has no single cause. The NHS and NICHD say the exact cause is unknown, but three things drive it: the body not responding properly to insulin, the ovaries making too much androgen (male-type hormone), and genes that run in families. A doctor diagnoses it when two of three features are present: irregular ovulation, signs of excess androgen, and polycystic ovaries on ultrasound.
Is PCOD the same as PCOS or PMOS?
Yes. PCOD (polycystic ovarian disease), PCOS (polycystic ovary syndrome) and PMOS (polyendocrine metabolic ovarian syndrome) are names for the same hormone condition. Indian clinics and labs mostly still write PCOD or PCOS. The NHS page, last reviewed on 30 June 2026, now carries the title "Polyendocrine metabolic ovarian syndrome (PMOS)" and states that "PMOS used to be called polycystic ovary syndrome (PCOS)". Cleveland Clinic uses the same new name. The US NICHD and MedlinePlus still use PCOS. This guide uses PCOS, because that is the term on most Indian prescriptions and reports.
Whatever the name, the condition is the same: the ovaries make unusually high levels of androgens, ovulation becomes irregular or stops, and the hormone imbalance affects hair, skin, weight, periods, fertility and mood.
PCOS is common. Cleveland Clinic says up to 15% of females of reproductive age have it. For India, a 2022 systematic review and meta-analysis in Cureus by Bharali and colleagues pooled 11 Indian studies published between 2010 and 2021 and found a prevalence of 11.33% (95% CI 7.69 to 15.59) using the Rotterdam criteria, with individual studies ranging from 4.2% to 22.5%. The authors note that most studies came from southern India and none from the east. Among Indian adolescent girls aged 14 to 19, a 2021 meta-analysis of 12 studies in the Nepal Journal of Epidemiology found a pooled prevalence of 17.74% by Rotterdam criteria, with community-based studies at about 11% and hospital-based studies at about 25%.
What causes PCOS?
Nobody has found a single cause. The NHS says the cause "is unknown" but that "it may be to do with hormones such as insulin and testosterone not working properly". NICHD says "genetic and environmental factors contribute to the development of PCOS" while "its exact cause remains unknown". The evidence points to three linked drivers that feed each other.
- Excess androgens. NICHD says women with PCOS have higher androgen levels and may have lower oestrogen. High androgen levels "can interfere with signals from the brain that control ovulation", so eggs do not mature and release on schedule. Cleveland Clinic puts it plainly: high androgen levels prevent the ovaries from releasing eggs.
- Insulin resistance. NICHD says many women with PCOS have cells that do not respond normally to insulin, so blood sugar rises, the pancreas makes more insulin, and the extra insulin pushes the ovaries to make more androgens.
- Genes. NICHD says the symptoms "tend to run in families" and that researchers have found 19 gene variants that raise risk. The NHS says you are more likely to have the condition "if a close relative has it or you are from an Asian background".
Two other factors appear in the sources. Cleveland Clinic says people with PCOS tend to have chronic low-grade inflammation, which doctors can measure with C-reactive protein and white blood cell tests. NICHD also reports animal research suggesting that exposure to high androgen levels in the womb may raise the likelihood of PCOS in daughters, though this is not proven in humans.
How does insulin resistance drive PCOS?
Insulin resistance drives PCOS by raising insulin levels, and high insulin tells the ovaries to make more androgens. NICHD describes the loop: when cells do not respond normally to insulin, blood sugar rises; the body makes more insulin to compensate; "to balance out the high levels of insulin, the body makes more androgens"; and the androgens then disrupt ovulation and worsen symptoms. NICHD adds that "it is difficult to disrupt this cycle, which is why treating PCOS can be challenging".
The numbers show how central insulin is. NICHD says more than half of women with PCOS have insulin resistance, about 4 in 5 also have obesity, and 25% to 45% have metabolic syndrome. Cleveland Clinic gives a wider range for obesity, 40% to 80%, and notes that obesity itself contributes to insulin resistance. The loop runs in both directions: weight gain worsens insulin resistance, and the hormone changes make weight harder to lose.
This is why the first blood tests a gynaecologist or endocrinologist orders usually include glucose, not only hormones. The 2023 international guideline says glycaemic status should be assessed at diagnosis in all adults and adolescents with PCOS, and that the 75 g oral glucose tolerance test is the most accurate test. It also explains why metformin, a diabetes medicine, appears in PCOS treatment: it improves the body's response to insulin, which lowers the signal for androgen production.
What are the symptoms of PCOS?
The main symptoms are irregular or missed periods, excess facial or body hair, acne, weight gain and difficulty getting pregnant. The NHS says symptoms usually start at puberty, continue until menopause, and can be mild, severe or absent. NICHD warns that the symptoms "vary widely and can seem unrelated", so doctors may not suspect PCOS at first.
| Symptom | What it points to | Source |
|---|---|---|
| Periods fewer than 8 a year, cycles over 35 days, or no periods | Irregular or absent ovulation | 2023 guideline, NICHD |
| Very heavy periods after long gaps | Womb lining built up without ovulation | NICHD |
| Hair on face, chest, belly or upper thighs (hirsutism) | Excess androgens; affects up to 70% of people with PCOS | Cleveland Clinic |
| Severe, late-onset or persistent acne; oily skin | Excess androgens | NICHD |
| Thinning scalp hair | Excess androgens | NHS, Cleveland Clinic |
| Weight gain around the waist, trouble losing weight | Insulin resistance | NICHD |
| Dark, velvety skin patches on neck or armpits (acanthosis nigricans); skin tags | Insulin resistance | NHS, NICHD, Cleveland Clinic |
| Difficulty getting pregnant | Anovulation; PCOS is a leading cause of female infertility | MedlinePlus, Cleveland Clinic |
| Low mood, anxiety, tiredness | Hormonal and metabolic effects | NHS |
Cleveland Clinic says some people have no symptoms at all and only find out when they struggle to conceive. The 2023 guideline says symptoms of depression and anxiety "are significantly increased and should be screened for in all women with PCOS".
Irregular periods in the first two or three years after periods start are normal and are not by themselves a sign of PCOS. The guideline's cycle thresholds apply from three years after the first period onward.
How is PCOS diagnosed under the Rotterdam criteria?
A doctor diagnoses PCOS when at least two of three features are present and other causes have been excluded. NICHD describes the three features: absent or irregular ovulation causing menstrual irregularities; high androgen levels, or signs of them such as increased body or facial hair, not caused by another condition; and growths of a specific size in one or both ovaries on ultrasound.The 2023 international guideline, published in the Journal of Clinical Endocrinology and Metabolism, sets the exact thresholds:
- Irregular cycles: from three years after the first period until perimenopause, cycles shorter than 21 days, longer than 35 days, or fewer than 8 cycles a year.
- Androgens: blood tests for total and free testosterone; free testosterone is estimated with the calculated free androgen index. Hirsutism alone counts as evidence of excess androgen in adults.
- Ultrasound: 20 or more follicles in at least one ovary, or an ovarian volume of 10 mL or more where image quality is limited. Serum AMH can replace ultrasound in adults but must not be the only test. Ultrasound is not recommended for diagnosing polycystic ovaries in adolescents, and the NHS says it only scans the ovaries of people over 18.
The guideline's diagnostic algorithm also lists the tests used to rule out look-alike conditions: TSH for thyroid disease, prolactin, 17-hydroxyprogesterone for adrenal causes, and FSH. A thyroid test and a pelvic ultrasound are available at most Indian diagnostic centres, and a gynaecologist or endocrinologist can order them.
Which check-ups should follow a PCOS diagnosis?
After diagnosis, the 2023 guideline recommends a lipid profile for every woman with PCOS, a glucose assessment at diagnosis, a blood pressure check every year, and screening for depression. These follow from the long-term risks. The NHS says PCOS can increase the risk of type 2 diabetes, high blood pressure, cardiovascular disease, non-alcoholic fatty liver disease and womb cancer, and that regular check-ups can reduce these risks. Cleveland Clinic adds endometrial hyperplasia, sleep apnoea, depression and anxiety to the list.
The womb-cancer risk comes from the period pattern. When ovulation does not happen, the lining of the womb builds up without being shed, and over years this can thicken abnormally. That is one reason doctors prescribe hormonal contraception even to women who are not trying to prevent pregnancy: it makes the lining shed regularly.
For pregnancy, Cleveland Clinic says most people with PCOS carry pregnancies successfully but have higher rates of gestational diabetes, pre-eclampsia, high blood pressure, preterm birth and caesarean delivery, so antenatal care needs to know about the diagnosis.
A practical check-up list, based on the guideline and the NHS:
- Fasting glucose or a 75 g oral glucose tolerance test at diagnosis, then as advised.
- A lipid profile at diagnosis.
- Blood pressure once a year.
- Weight and waist, with the guideline noting that clinicians should ask permission before weighing.
- A screening conversation about mood, sleep and anxiety.
In India these tests are inexpensive at government hospitals and most private labs; the links above show typical price ranges by city.
How is PCOS treated?
Treatment targets the symptom that bothers you most, because there is no cure. The NHS says "there is no cure, but treatments and lifestyle changes can help".
Lifestyle first. The 2023 guideline says lifestyle intervention "should be recommended for all women with PCOS". NICHD says "losing a small amount of weight and being more physically active can minimize many PCOS symptoms" and that weight loss "can restore ovulation and help make menstrual cycles more regular". The NHS advises a balanced diet, regular exercise and losing weight if overweight.
For irregular periods, acne and hair. NICHD says combined oral contraceptives containing oestrogen and progestin are "the primary long-term treatment option". The guideline says the combined pill "could be recommended" for hirsutism or irregular cycles. The NHS lists the combined pill, progestogen-only pill or intrauterine system for periods, and spironolactone or eflornithine for unwanted hair, alongside laser or electrolysis.
For insulin resistance. The guideline says metformin "should be considered" in adults with a BMI of 25 or above. NICHD says some women start ovulating naturally after 4 to 6 months on it.
For fertility. The guideline says letrozole "should be the first-line pharmacological treatment for ovulation induction". The NHS lists clomifene, and laparoscopic ovarian drilling when other treatments have not worked. Cleveland Clinic lists injectable gonadotropins and IVF for women who still do not ovulate.
For fertility treatment, ask the gynaecologist what a government or Ayushman-empanelled hospital offers before paying privately. This guide is general information from the sources listed below, not medical advice; a registered doctor makes decisions with you.
