Polycystic ovary syndrome explained

Understanding PCOS

PCOS is a complex hormonal condition with multiple features. Knowing the underlying biology helps make sense of the symptoms.

The basic biology

PCOS involves three core features: irregular or absent ovulation, signs of elevated androgens (the testosterone family) and often polycystic ovaries on ultrasound. The exact cause is not fully understood but involves insulin resistance, genetic factors and possibly environmental influences. The hormonal patterns of PCOS reinforce each other, creating the cluster of symptoms women experience.

The misleading name

The name suggests cysts on the ovaries are the central feature but this is misleading. The "cysts" are actually partially developed follicles, eggs that started maturing but did not complete the process. The presence of polycystic ovaries on scan is one diagnostic feature but not the most important. Women can have PCOS without polycystic ovaries visible on ultrasound.

Insulin at the centre

Insulin resistance is at the heart of PCOS for most women. The body produces normal or higher insulin levels but cells respond poorly. The high insulin drives the ovaries to produce more androgens, which disrupts the normal hormonal pattern of the menstrual cycle. This is why PCOS symptoms often improve when insulin sensitivity improves.

The genetic component

PCOS runs in families. Daughters of women with PCOS have higher risk. The condition is not directly inherited but the genetic predisposition is significant. Environmental factors including diet, weight and lifestyle determine whether the predisposition becomes active disease for many women. Family history is worth knowing.

What PCOS looks like

PCOS produces a cluster of symptoms. The specific combination varies between women, which is part of why diagnosis can be tricky.

Irregular cycles

Cycles longer than 35 days, very irregular cycles or absent periods are common features. Some women have periods every few months. Others have heavy or prolonged bleeding when periods do come. Some women on hormonal contraception have masked cycles, which can delay PCOS diagnosis. Tracking your natural cycle (when not on the pill) reveals the pattern.

Skin and hair

Acne persisting into adulthood or appearing for the first time as an adult is common. Excess hair growth on the face, chest or abdomen affects many women with PCOS. Hair thinning on the scalp can occur. Skin tags and darkened skin patches in body folds (acanthosis nigricans) reflect insulin resistance. These visible signs can be distressing.

Weight and metabolism

Many women with PCOS struggle with weight, particularly around the abdomen. Insulin resistance makes weight gain easier and weight loss harder than for women without PCOS. Energy crashes, intense cravings and difficulty losing weight despite reasonable effort all suggest the metabolic aspect of PCOS. Not all women with PCOS are overweight. Metabolic issues are common regardless.

Fertility and other features

Difficulty conceiving brings many women to PCOS diagnosis. Mood symptoms including anxiety and depression are more common. Sleep apnoea occurs more frequently, particularly with higher weight. Fatty liver and other metabolic conditions can develop. The full picture extends well beyond cycles and unwanted hair.

Getting the right care

PCOS diagnosis and management benefit from active engagement. Knowing what to expect helps you advocate for yourself.

The diagnostic process

Diagnosis uses the Rotterdam criteria: any two of three features (irregular ovulation, signs of excess androgens, polycystic ovaries on scan), with other conditions ruled out. Blood tests check testosterone, SHBG, prolactin, thyroid function, FSH and LH. Metabolic markers including blood sugar and cholesterol are typically checked. Ultrasound may show polycystic ovaries.

Treatment by priority

Treatment depends on what matters most to you. For irregular cycles, the combined pill or hormonal IUD often works. For acne and unwanted hair, the combined pill helps many women. For fertility, ovulation induction with letrozole or clomifene is typically first line. For metabolic concerns, metformin and lifestyle changes are central. Different priorities lead to different approaches.

Lifestyle as treatment

Lifestyle changes are particularly powerful in PCOS because they target the underlying insulin resistance. Strength training, walking, eating real food, limiting refined carbohydrates and adequate sleep all help. The benefits are larger in PCOS than in women without the condition because the underlying biology is more responsive. These are not optional add ons but core treatment.

Ongoing care

PCOS is lifelong and benefits from ongoing review rather than one off treatment. Annual reviews including blood pressure, weight, cholesterol and blood sugar are reasonable. Symptoms that change should be discussed. Treatment can be adjusted as life circumstances and priorities change. Speak to your GP about establishing a review pattern.

PCOS through life

PCOS does not stay the same across decades. Understanding how it evolves helps you plan accordingly.

In adolescence and twenties

PCOS often becomes apparent in adolescence with irregular cycles, acne and unwanted hair. Diagnosis can be tricky because some PCOS features overlap with normal pubertal changes. Twenties often see acne and unwanted hair at their most prominent. Building good lifestyle habits during these years pays off long term. Active management early prevents some of the later problems.

During reproductive years

Fertility considerations often dominate the thirties for women with PCOS. Many conceive with appropriate support. Some need fertility treatment. Pregnancy carries slightly elevated risks but most go well with good antenatal care. The metabolic side of PCOS continues to need attention even when reproductive priorities are met.

Through midlife

The metabolic and cardiovascular risks of PCOS become more prominent in midlife. Type 2 diabetes risk is elevated. Cardiovascular risk warrants active management. Perimenopause for women with PCOS may be slightly delayed but symptoms can be more disruptive. Ongoing engagement with lifestyle and where appropriate medication remains important.

After menopause

PCOS does not disappear at menopause. The cycle related symptoms resolve when cycles stop but the metabolic and cardiovascular risks continue. Regular health checks remain important. The active management that served you through reproductive years continues to pay off. PCOS truly is lifelong.

More on female health

For practical management, our PCOS: Symptoms Diagnosis and Management covers day to day care. How PCOS Affects Fertility covers the fertility aspect. And The Long Term Health Risks of PCOS covers the longer view.