Polycystic Ovary Syndrome (PCOS)

PCOS is a hormonal and metabolic disorder characterized by irregular periods, ovarian cysts, insulin resistance, and weight gain—strongly associated with obesity and metabolic dysfunction.

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Overview

Polycystic ovary syndrome (PCOS) is the most common hormonal disorder in women of reproductive age, affecting roughly 10% to 13% of women worldwide (Teede et al., International Evidence-based PCOS Guideline, Journal of Clinical Endocrinology & Metabolism, 2023). It is defined by a combination of irregular or absent ovulation, signs of excess androgens (male-type hormones) such as acne and excess hair growth, and ovaries that contain many small follicles on ultrasound. Despite its name, PCOS is fundamentally a metabolic and hormonal condition, not simply a disease of the ovaries.

PCOS is closely tied to insulin resistance and weight. Many women with PCOS have overweight or obesity, and excess weight worsens insulin resistance, which in turn raises androgen levels and disrupts ovulation. The cycle can be difficult to break, but even modest weight loss of 5% to 10% can restore regular cycles and ovulation in many women (Teede et al., International Evidence-based PCOS Guideline, Journal of Clinical Endocrinology & Metabolism, 2023).

PCOS carries long-term health implications beyond fertility, including higher risks of type 2 diabetes, heart disease, fatty liver disease, sleep apnea, depression and endometrial cancer. Effective care therefore addresses symptoms, fertility goals and metabolic health together.

PCOS and Insulin Resistance

Most women with PCOS have some degree of insulin resistance, including many who are not overweight. When cells respond poorly to insulin, the pancreas produces more of it, and high insulin levels act directly on the ovaries to increase androgen production while lowering a protein (SHBG) that normally binds and inactivates testosterone. The result is more active androgen, irregular ovulation, acne and hair growth. This is why treatments that improve insulin sensitivity, such as weight loss, exercise, metformin and GLP-1 medications, often improve PCOS symptoms.

Does Everyone With PCOS Have Cysts?

No. The "cysts" are actually small immature follicles, not true cysts, and some women with PCOS have normal-appearing ovaries. Conversely, many women without PCOS have multiple follicles on ultrasound. The diagnosis depends on the combination of features, not ultrasound alone (Teede et al., Journal of Clinical Endocrinology & Metabolism, 2023).

Causes

Insulin resistance and high insulin levels, which stimulate the ovaries to produce more androgens (Teede et al., International Evidence-based PCOS Guideline, Journal of Clinical Endocrinology & Metabolism, 2023)
Hormonal imbalance: elevated luteinizing hormone (LH) relative to FSH disrupts follicle development
Genetics: PCOS strongly runs in families
Excess weight, particularly abdominal fat, which amplifies insulin resistance
Low-grade inflammation
Developmental factors, including the hormonal environment before birth

Risk Factors

Family history of PCOS or type 2 diabetes
Overweight or obesity
Insulin resistance or prediabetes
Early or irregular puberty
Certain ethnic backgrounds, with higher metabolic risk in some groups

Who It Affects

PCOS affects women from adolescence through menopause. Symptoms often begin around puberty, but many women are not diagnosed until they experience difficulty conceiving or weight gain in their twenties or thirties. Women with PCOS are overrepresented among patients seeking medical and surgical weight-loss treatment.

Lean women can also have PCOS. In these women, insulin resistance may still be present, and treatment focuses on cycle regulation, androgen symptoms and fertility rather than weight loss.

Complications

Infertility from irregular ovulation; PCOS is the most common cause of ovulatory infertility
Type 2 diabetes and gestational diabetes
Heart disease risk factors: high blood pressure and abnormal cholesterol
Fatty liver disease
Sleep apnea
Endometrial hyperplasia and cancer from long periods without menstruation
Depression, anxiety and eating disorders
Pregnancy complications, including preeclampsia

Women with PCOS should be screened for diabetes with an oral glucose tolerance test or HbA1c every one to three years, and before pregnancy, because their risk is several times higher than average (Teede et al., Journal of Clinical Endocrinology & Metabolism, 2023).

Symptoms

Irregular, infrequent or absent periods
Difficulty getting pregnant
Excess facial or body hair (hirsutism)
Acne and oily skin
Scalp hair thinning
Weight gain, especially around the abdomen, and difficulty losing weight
Dark, velvety skin patches on the neck or armpits (acanthosis nigricans)
Mood changes, anxiety or depression

Diagnosis

In adults, PCOS is diagnosed when at least two of three features are present, after other causes are excluded (Rotterdam ESHRE/ASRM Consensus, Human Reproduction, 2004) (Teede et al., International Evidence-based PCOS Guideline, Journal of Clinical Endocrinology & Metabolism, 2023):

Irregular or absent ovulation
Clinical or laboratory signs of high androgens
Polycystic ovaries on ultrasound, or an elevated anti-Müllerian hormone (AMH) level, which the 2023 guideline accepts as an alternative in adults (Teede et al., International Evidence-based PCOS Guideline, Journal of Clinical Endocrinology & Metabolism, 2023)

Testing also includes thyroid function, prolactin and other hormones to exclude look-alike conditions, and screening for diabetes, cholesterol problems, high blood pressure and sleep apnea.

PCOS in Adolescents

Diagnosing PCOS in teenagers is more difficult, because irregular cycles and acne are common in the first years after periods begin. Guidelines recommend requiring both irregular cycles and androgen excess in adolescents and not relying on ultrasound or AMH in this age group (Teede et al., Journal of Clinical Endocrinology & Metabolism, 2023). Teens with features of PCOS may be considered "at risk" and reassessed later.

Differential Diagnosis

Thyroid disease
High prolactin
Non-classic congenital adrenal hyperplasia
Cushing syndrome
Androgen-secreting tumors
Hypothalamic amenorrhea from low weight or excessive exercise

Lifestyle Modifications

Lifestyle change is the foundation of PCOS treatment for all women (Teede et al., International Evidence-based PCOS Guideline, Journal of Clinical Endocrinology & Metabolism, 2023):

Aim for 5% to 10% weight loss if you have overweight or obesity; this often restores ovulation.
Choose a balanced, sustainable eating pattern; no single diet is superior for PCOS.
Exercise at least 150 minutes per week, including strength training, which improves insulin sensitivity.
Prioritize sleep and get evaluated for sleep apnea.
Seek support for mood and body image concerns.

Practical Steps That Help

Build meals around protein and fiber, which blunt blood sugar spikes and help control hunger.
Limit sugary drinks and refined carbohydrates.
Combine aerobic exercise with resistance training; building muscle improves insulin sensitivity even before weight changes.
Track cycles with an app to see how lifestyle changes affect ovulation.
Set realistic goals: small, steady weight loss is more sustainable and still effective.

Treatment Options

Medical Therapy

Combined oral contraceptives: regulate cycles, protect the uterine lining and reduce acne and hair growth (Teede et al., International Evidence-based PCOS Guideline, Journal of Clinical Endocrinology & Metabolism, 2023)
Metformin: improves insulin resistance and may help cycles and weight, particularly in women with higher BMI
Anti-androgen medications such as spironolactone for hirsutism, used with contraception
Anti-obesity medications: GLP-1 receptor agonists and tirzepatide can produce substantial weight loss and improve metabolic features; they are stopped before attempting pregnancy. See medical weight loss.

Fertility Treatment

Letrozole is the first-line medication to induce ovulation; in a large randomized trial it led to more live births than clomiphene in women with PCOS (Legro et al., New England Journal of Medicine, 2014). IVF is used when other treatments are unsuccessful.

Bariatric Surgery

For women with PCOS and severe obesity, bariatric surgery produces large, sustained weight loss and improves menstrual regularity, hirsutism and metabolic health; a meta-analysis found PCOS features resolved in the majority of women after surgery (Skubleny et al., Obesity Surgery, 2016). Pregnancy should generally be postponed for 12 to 18 months after surgery, and reliable contraception is important because fertility often returns quickly. See bariatric surgery and the pregnancy and contraception guide.

Treating Specific Symptoms

Irregular periods: hormonal contraception or cyclic progestin protects the uterine lining.
Hirsutism: contraceptives and anti-androgens reduce new growth over six to twelve months, combined with laser hair removal or other cosmetic methods.
Acne: contraceptives, topical treatments and anti-androgens
Hair thinning: anti-androgens and topical minoxidil
Weight and metabolic health: lifestyle, medication and, for severe obesity, bariatric surgery

When to See a Doctor

See a doctor if your periods are irregular or absent, you have trouble conceiving, or you notice excess hair growth, persistent acne or rapid weight gain.

If you have PCOS and are planning a pregnancy, see your doctor beforehand to check blood sugar, start folic acid and discuss whether weight loss before conception would improve your chances and reduce pregnancy risks.

When to Seek Treatment

Seek prompt care for heavy or prolonged bleeding after months without a period, symptoms of high blood sugar, or severe mood changes.

Long-Term Outlook

With ongoing attention to weight, blood sugar, cholesterol, blood pressure and mental health, women with PCOS can greatly reduce their long-term risks. Many achieve pregnancy with treatment, and symptoms often ease after menopause.

Because PCOS increases lifelong cardiometabolic risk, regular checks of blood pressure, cholesterol, blood sugar and weight should continue after childbearing years and through menopause.

Prognosis

PCOS is a lifelong condition, but symptoms and risks can be controlled very effectively. Weight loss, whether through lifestyle, medication or surgery, is one of the most powerful tools for restoring ovulation and improving metabolic health (Teede et al., International Evidence-based PCOS Guideline, Journal of Clinical Endocrinology & Metabolism, 2023).

Women who achieve and maintain weight loss often see more regular cycles within months, improved fertility, and better blood sugar and cholesterol. Hair growth and acne respond more slowly, usually over six to twelve months of treatment.

Why Choose Dr. de la Cruz-Muñoz

For many women, PCOS and obesity are two sides of the same problem. Dr. de la Cruz-Muñoz is a board-certified metabolic and bariatric surgeon whose practice offers medical weight loss with GLP-1 medications and the full range of bariatric operations, coordinated with gynecologists and fertility specialists. Women receive guidance on contraception and the timing of pregnancy after surgery to protect both mother and baby.

Dr. de la Cruz-Muñoz co-authored research on the effects of bariatric surgery on cardiometabolic risk factors in ethnically diverse women with PCOS (Meade et al., World Journal of Diabetes, 2013).

Dr. de la Cruz-Muñoz has been performing bariatric surgery for over 25 years and has completed more than 9,000 bariatric operations — a volume few surgeons reach.