Polycystic Ovary Syndrome (PCOS): Causes, Symptoms, and Modern Treatment

Irregular cycles, persistent acne, increased body hair, weight gain, and a desire to become pregnant that just won’t take off: these can all be signs of polycystic ovary syndrome (PCOS). It is one of the most common hormonal conditions in people of reproductive age worldwide and a major cause of cycle problems and anovulatory infertility. This guide explains in clear terms what PCOS is, how to recognize typical signs, how the diagnosis is made according to current guidelines, and which elements of treatment are considered useful today.

What is PCOS? More than just “cysts on the ovaries”

PCOS is not a single symptom but a syndrome. It describes a recurring pattern of hormonal and metabolic features that can look different in each person. Typical is a combination of:

• elevated androgens such as testosterone or visible signs of androgen excess like hirsutism and acne
• disturbances of ovulation and cycle with infrequent or absent bleeding
• many small, immature follicles in the ovaries that appear like cysts on ultrasound

Important clarification: these follicles are usually not “true” cysts but early follicles that do not mature to ovulation. PCOS is therefore a chronic dysfunction of hormonal regulation and metabolism, not an irreversible defect of the ovaries.

How common is PCOS worldwide?

Large reviews and international organizations estimate that about 8 to 13 percent of people with ovaries of reproductive age meet criteria for PCOS, depending on the definition and the population studied. Many affected people are diagnosed late because cycle irregularities, acne, or excess hair growth are often dismissed as “normal” for a long time or attention is focused only on contraception.

Current fact sheets from international health organizations, for example the PCOS factsheet of the WHO, and international guidelines emphasize that PCOS affects more than fertility: it can impact blood sugar, blood pressure, cardiovascular risk, and mental health.

Recognizing typical PCOS symptoms early

PCOS typically presents in late puberty or young adulthood, but sometimes only becomes apparent when fertility issues arise. Common PCOS symptoms include:

• irregular menstruation, cycles longer than 35 days, or absent bleeding
• very heavy or very light bleeding without an obvious cause
• increased hair growth on the face, chin, chest, abdomen, or back
• persistent acne or very oily skin beyond adolescence
• thinning scalp hair or hair loss at the forehead or crown
• weight gain, especially central abdominal weight, often despite unchanged eating habits
• fatigue, strong cravings, and wide daily fluctuations in energy levels
• difficulty becoming pregnant because ovulation is absent or unpredictable

No one has all the features. Even single signs such as cycles consistently longer than 35 days or pronounced hirsutism are clear reasons to discuss PCOS with a clinician.

Causes and mechanisms — why PCOS develops

The exact cause of PCOS is not fully understood. Research points to an interplay of genetic predisposition, hormonal regulatory networks, and environmental factors. Studies from large U.S. research centers describe the syndrome as a cluster of symptoms centered on hormonal changes involving androgen excess and insulin resistance.

• Genetic predisposition: PCOS can run in families. First-degree relatives have a clearly increased risk of developing PCOS-related features.
• Insulin resistance: Many people with PCOS are less sensitive to insulin. The body produces more insulin, which stimulates androgen production in the ovaries and disrupts egg maturation.
• Weight and body composition: Excess weight can exacerbate existing insulin resistance, but it is not a prerequisite. Many people with PCOS are lean.
• Environment and lifestyle: Diet, stress, sleep, and physical activity influence how strongly genetic predisposition is expressed, but do not explain PCOS by themselves.

An important takeaway: PCOS is not a “punishment” for lifestyle choices but a biological predisposition whose effects you can influence with the right measures.

Diagnosis according to guidelines — Rotterdam criteria and more

PCOS is a diagnosis of exclusion. Before making the diagnosis, clinicians check whether other conditions could explain the symptoms, for example thyroid disorders, elevated prolactin, or rare genetic causes. Only when such alternatives are excluded is PCOS considered.

Many professional societies use three core criteria commonly referred to as the Rotterdam criteria:

• infrequent or absent ovulation with irregular or missing menstrual periods
• clinical signs of androgen excess such as hirsutism or acne, or elevated androgen levels in the blood
• polycystic ovaries on ultrasound with many small follicles

Generally, at least two of these three features must be present for a PCOS diagnosis. A large international evidence-based guideline on PCOS diagnosis and treatment, accessible through professional societies such as the American College of Obstetricians and Gynecologists, summarizes these criteria and concrete diagnostic pathways and emphasizes the importance of an informative, shared decision-making discussion with patients.

Public health portals and international organizations such as the WHO explain in plain language how the diagnosis is made and offer practical everyday tips.

Special considerations apply to adolescents: puberty-related symptoms like acne and irregular cycles are common even without PCOS. Guidelines therefore recommend caution with the diagnosis in youth and favor watchful follow-up rather than a premature label.

Long-term risks — PCOS affects the whole body

PCOS is not only a fertility issue. Without appropriate management it can increase the risk of several physical conditions:

• impaired glucose tolerance, prediabetes, and type 2 diabetes
• high blood pressure, unfavorable blood lipids, and metabolic syndrome
• cardiovascular disease later in life
• sleep apnea, especially with higher body weight
• thickening of the uterine lining with an increased risk of endometrial cancer if bleeding is very infrequent or absent
• pregnancy complications such as gestational diabetes or high blood pressure

For these reasons, international guidelines recommend regular monitoring of blood pressure, blood glucose, lipids, and weight regardless of whether pregnancy is currently desired. A major review by an endocrinology society highlights the importance of viewing PCOS as a lifelong health factor, not only a problem of the twenties and thirties.

Diet and exercise — the foundation of any PCOS treatment

Lifestyle is the first recommendation in nearly all PCOS guidelines. It does not replace medical therapy but can substantially enhance its effects. Even a moderate, sustained weight loss of five to ten percent can noticeably improve cycle regularity, hormones, and metabolism in people with overweight.

• Blood-glucose–friendly diet: Plenty of vegetables, legumes, whole grains, nuts, and healthy fats help stabilize blood sugar and insulin. Sugary drinks, sweets, and highly processed snacks should be occasional.
• Regular exercise: At least 150 minutes of moderate aerobic activity per week plus one to two strength-training sessions are recommended. Exercise improves insulin sensitivity independent of weight and benefits mood and sleep.
• Stable routines: Adequate sleep, regular meal timing, and stress-reduction strategies help buffer hormonal fluctuations.
• Supplements: Substances such as myo-inositol or D-chiro-inositol are under active investigation. Information from the U.S. National Institute of Child Health and Human Development on PCOS shows they may support cycle and metabolic regulation in some people but should always be part of a comprehensive plan.

More important than the perfect regimen is that the plan fits your daily life. Extreme diets, quick fixes, and prohibitions rarely produce lasting benefits and can worsen bingeing, weight fluctuations, and frustration.

Medical treatment — what options exist

Which medications are appropriate depends on your goals, lab results, and life stage. Modern guidelines emphasize a stepwise approach with active involvement of the patient.

• Combined hormonal contraception: Birth control pills, patches, or vaginal rings can regulate cycles and bleeding, reduce menstrual discomfort, and improve acne or hirsutism. They are suitable when pregnancy is not currently desired.
• Metformin: This medication improves insulin sensitivity and is commonly used for insulin resistance, prediabetes, or elevated diabetes risk. It can have beneficial effects on weight, blood sugar, androgen levels, and cycles.
• Antiandrogens: Agents such as spironolactone or certain progestins can reduce excessive hair growth and acne. They must always be combined with reliable contraception because they can harm an unborn child.
• Ovulation induction: For active fertility desires, international guidelines often recommend letrozole as the first-line medication to induce ovulation. Clomiphene is an alternative but is increasingly being replaced by letrozole.
• Gonadotropins: Injectable hormones are used when oral medications are insufficient. They require close ultrasound monitoring to avoid ovarian hyperstimulation and multiple pregnancy.
• Weight-management medications: In some countries, medications that promote weight loss and improve metabolism are used for marked obesity. Their use should be individualized and evidence-based within specialized teams.

Clear, patient-friendly overviews of diagnosis and treatment are available from organizations such as the American Society for Reproductive Medicine (ASRM) and the U.S. National Institute of Child Health and Human Development (NICHD), which explain lifestyle measures, medications, and fertility treatments in detail.

PCOS and fertility — take a systematic approach

1. Optimize the basics

Before any medical fertility treatment, it is worthwhile to address the basics. A blood-glucose–friendly diet, weight reduction if overweight, smoking cessation, moderate alcohol intake, and increased physical activity improve spontaneous ovulation rates and the success of any subsequent therapy.

2. Make ovulation visible

Many people with PCOS ovulate irregularly or not at all. Cycle tracking with basal body temperature charts, ovulation tests, observation of cervical mucus, and, when appropriate, ultrasound help to better detect ovulation. At the same time, other factors such as sperm quality and tubal patency should be evaluated.

3. Ovulation induction and intrauterine insemination

If spontaneous ovulation is absent, letrozole or clomiphene are used to stimulate egg development. Depending on the situation, intrauterine insemination (IUI), where prepared sperm are placed directly into the uterus, may be beneficial.

4. IVF and ICSI

If pregnancy does not occur despite ovulation induction or if additional factors are present, procedures such as in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) are considered. People with PCOS have an increased risk of ovarian hyperstimulation syndrome, so stimulation protocols and trigger timing must be planned carefully.

5. Information from reliable sources

The U.S. National Institute of Child Health and Human Development provides dedicated pages on PCOS and fertility with detailed explanations of hormonal stimulation, ovulation induction, IUI, IVF, and ICSI. Such resources are good starting points to make the most of your medical appointments.

PCOS across the lifespan — from puberty to menopause

PCOS accompanies people for decades, but its impact varies. In adolescence, acne, cycle irregularities, and body image concerns are often most prominent. Later, fertility, weight, blood pressure, and blood sugar become central. In perimenopause hormones change again; some symptoms improve while others, such as cardiovascular risk, become more important.

Good PCOS management is therefore dynamic. The goal is not a rigid lifetime protocol but to find, in each life phase, a sensible mix of lifestyle, medical treatment, and psychological support.

Mental health — PCOS is also a psychological challenge

PCOS is more than lab results. Studies show higher rates of depressive symptoms, anxiety disorders, eating disorders, and body dissatisfaction. Visible changes such as acne, increased hair growth, or weight gain collide with societal ideals and can strongly affect self-esteem and relationships.

It is worthwhile to consider mental health from the start. Open conversations with family and clinicians, good patient–provider communication, psychotherapy, nutritional counseling, exercise coaching, and peer support groups can help frame PCOS as a manageable condition rather than a personal failure. A stable psychological foundation increases the likelihood of sustaining medical and daily-life measures over the long term.

When should you see a doctor for suspected PCOS?

You should seek medical advice if your cycle is clearly irregular over several months, your period is absent for more than three months, or you have very infrequent bleeding. New-onset hirsutism, persistent acne, unexplained rapid weight gain, marked fatigue, or an unfulfilled desire for pregnancy for twelve months—or for people in their mid-30s often after six months—are warning signs.

Acute symptoms such as severe lower abdominal pain, sudden one-sided pain, fever, circulatory problems, or very heavy bleeding require immediate medical assessment. PCOS cannot be reliably self-diagnosed. A structured evaluation with medical history, blood tests, and ultrasound is the most important step to gain clarity and develop a sensible plan.

Conclusion — understand PCOS and manage it with confidence

PCOS is common, complex, and still under-recognized, but better data, modern guidelines, and a wider range of treatment options are available today than ever before. With a combination of blood-glucose–friendly diet, regular exercise, individualized medical therapy, and long-term follow-up, cycles, skin, metabolism, and fertility can improve substantially for many people. Take time to understand your body, use information from reliable sources, and assemble a care team that listens and makes shared decisions with you. PCOS is a chronic but manageable predisposition—the better you know it and the more closely treatment and daily life fit you, the more control you regain over health, family planning, and quality of life.