Causes and Risk Factors
The exact cause is not known, but several interconnected factors drive the syndrome:- Insulin resistance: Present in a majority of women with PCOS regardless of weight; high insulin levels stimulate the ovaries to make more androgen.
- Excess androgen: Responsible for many visible symptoms and for interfering with ovulation.
- Genetics: PCOS clusters in families, and having an affected mother or sister raises the risk.
- Weight: Excess weight worsens insulin resistance and symptoms, though PCOS also affects lean women.
- Low-grade inflammation: Women with PCOS often show mild chronic inflammation, which is thought to contribute to both androgen excess and metabolic risk.
Symptoms
Symptoms usually begin around the time of the first menstrual periods, though they may emerge later:- Irregular or absent periods: Infrequent ovulation leads to cycles that are unpredictable, far apart, or missing.
- Excess hair growth (hirsutism): Coarse hair on the face, chest, or back.
- Acne and oily skin: Androgen-driven acne that often persists past adolescence.
- Thinning scalp hair: A male-pattern distribution of hair loss.
- Weight gain and difficulty losing weight: Reflecting the underlying insulin resistance.
- Difficulty becoming pregnant: A frequent reason PCOS first comes to medical attention.
- Darkened skin patches: Velvety darkening at the neck and skin folds (acanthosis nigricans), a marker of insulin resistance.
Diagnosis
There is no single test. PCOS is diagnosed when at least two of three features are present — irregular ovulation, clinical or laboratory evidence of excess androgen, and polycystic-appearing ovaries on ultrasound — after other causes are excluded. Blood tests typically include androgen levels, thyroid function, and prolactin, plus screening for the metabolic problems that travel with PCOS: fasting glucose or A1C for prediabetes (impaired fasting glucose) and a lipid panel. Conditions that can imitate PCOS — thyroid disease, elevated prolactin from a pituitary source, and rarer disorders of adrenal hormone production — are ruled out first, because their treatment is entirely different. Ultrasound is not required when the other two features are clearly present, and "polycystic" ovaries alone, without irregular cycles or androgen excess, do not establish the diagnosis.Treatment
Treatment is tailored to each woman's main concerns — cycle regulation, skin and hair symptoms, fertility, or metabolic health:- Lifestyle change: Even a 5 to 10 percent weight loss can restore ovulation and improve insulin resistance.
- Combined hormonal contraceptives: Pills containing an estrogen and a progestin such as levonorgestrel-ethinyl estradiol regulate cycles, lower androgens, and improve acne and hair growth.
- Metformin: Improves insulin sensitivity, supports weight efforts, and can help restore regular cycles.
- Spironolactone: Blocks androgen effects on skin and hair; used with reliable contraception.
- Fertility treatment: Medications that induce ovulation are effective for many women with PCOS who wish to conceive.
Complications
PCOS is a lifelong metabolic condition as much as a reproductive one, and several of its risks accumulate quietly over decades:- Prediabetes and type 2 diabetes: Insulin resistance makes diabetes substantially more likely, and it often appears at a younger age than usual.
- Cardiovascular and metabolic risk: High triglycerides (hypertriglyceridemia), high blood pressure, and fatty liver disease all occur more frequently.
- Overgrowth of the uterine lining: Cycles without ovulation leave the lining exposed to estrogen unopposed by progesterone, which over years increases the risk of endometrial hyperplasia and uterine cancer — a key reason to regulate cycles even when pregnancy is not the goal.
- Obstructive sleep apnea: More common in PCOS than in other women of the same weight, and it worsens both insulin resistance and daytime fatigue.
- Anxiety and depression: Mood symptoms occur more often with PCOS and deserve to be asked about directly rather than waited for.
Living With PCOS Over the Long Term
PCOS treatment is chosen around the problem that matters most right now, and that changes over a lifetime: skin and cycles in the twenties, fertility in the thirties, blood sugar and cholesterol after that. What follows is what to expect from each option and what needs checking regardless of which one you are on.
Skin and hair improve slowly
A combined pill such as levonorgestrel-ethinyl estradiol lowers androgen levels within weeks, but hair follicles respond on a months-long cycle, so hirsutism and acne take about six months to show clear change. Spironolactone is usually added when the pill alone is not enough and works on the same timescale; hair already grown is removed by laser or electrolysis rather than medication. Judging a treatment at six weeks and switching is the most common reason nothing seems to work.
Protecting the uterine lining without the pill
Women who cannot or prefer not to take estrogen still need the lining shed regularly. A progestin such as norethindrone for a stretch of days every one to three months, a hormonal IUD, or restoring ovulation through weight loss and metformin all accomplish this. Going more than three months without a period is a reason to call, not wait.
Fertility: the first-line drug has changed
Letrozole now produces higher live-birth rates than clomiphene for ovulation induction in PCOS and is the usual first choice, with metformin sometimes added. Losing even a modest amount of weight before starting improves the odds and the safety of pregnancy, and prediabetes is addressed first because it raises the risk of gestational diabetes.
Metformin and weight medication
Metformin's stomach upset fades if the dose is raised gradually over several weeks and taken with food, and the extended-release form is gentler. In women with obesity, GLP-1 medications such as semaglutide produce weight loss that often restores cycles, but they are stopped before trying to conceive, and reliable contraception is needed while on them because ovulation can return without warning. Our PCOS and insulin resistance article covers the metabolic side in depth.
The checks that continue for life
An A1C or glucose test every one to three years from diagnosis, a lipid panel, and blood pressure at every visit catch the transition from impaired fasting glucose to diabetes early. Loud snoring or daytime sleepiness prompts testing for sleep apnea, elevated liver enzymes prompt evaluation for fatty liver disease, and mood is asked about directly. Our endocrine team coordinates these with gynecology. NICHD and the Office on Women's Health publish patient guidance on PCOS.
If your PCOS plan was set years ago and has not been revisited since, schedule a visit.