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What are the three main features of PCOS?

PCOS, or polycystic ovary syndrome, is a common hormonal disorder that affects women. The three main features of PCOS are:

Irregular periods

Women with PCOS often have irregular menstrual cycles. This means their periods may be very light, very heavy, or absent for several months. Irregular periods are one of the most common symptoms of PCOS and are usually one of the first signs that leads women to seek medical advice.

Some key facts about irregular periods in PCOS:

  • At least 70% of women with PCOS have irregular menstrual cycles.
  • Menstrual cycles may be very long (35 days or more) or very short (less than 21 days).
  • Some women may only have 4-6 periods per year.
  • Some women may stop having periods altogether for several months or years, known as amenorrhea.

The reason for irregular periods in PCOS is due to abnormalities in ovulation. Most women with PCOS either ovulate infrequently or not at all. This disrupts the normal hormonal fluctuations that control the menstrual cycle, leading to irregular bleeding.

Excess androgens

Women with PCOS tend to have higher than normal levels of male hormones, known as androgens. The main androgens implicated in PCOS are testosterone and androstenedione.

Some key facts about excess androgens in PCOS:

  • Up to 80% of women with PCOS have elevated androgen levels.
  • The most common symptoms are hirsutism (excess facial and body hair), acne, and male-pattern balding.
  • Androgens directly cause these symptoms by stimulating hair follicles in the skin.
  • The excess androgens primarily come from the ovaries, but the adrenal glands may also be involved.

The high androgen levels prevent normal ovulation and disrupt the menstrual cycle. They also cause the troubling cosmetic symptoms that affect self-esteem.

Polycystic ovaries

Polycystic ovaries (PCO) are enlarged ovaries that contain many small fluid-filled sacs called follicles.

  • Up to 90% of women with PCOS have polycystic ovaries on ultrasound.
  • However, polycystic ovaries alone do not confirm PCOS. They must occur along with irregular periods and/or high androgens.
  • The many small follicles prevent the ovaries from releasing an egg normally (ovulating).

The combination of these three main features is what defines PCOS. Having just one or two of the symptoms is not sufficient for a PCOS diagnosis – they must occur together.

What causes PCOS?

While the exact cause of PCOS is unknown, it is thought to be related to abnormalities in hormone levels and insulin regulation. There are likely genetic factors as well, since PCOS tends to run in families.

Some of the main factors believed to contribute to PCOS include:

Insulin resistance

Insulin resistance is thought to be central to the development of PCOS. Up to 80% of women with PCOS have some degree of insulin resistance. When the body’s cells do not respond well to insulin, more insulin is produced to try to compensate.

Excess insulin:

  • Increases androgen production, leading to symptoms like facial hair growth and irregular periods.
  • Interferes with normal ovulation.
  • May directly cause the polycystic ovary morphology.

Treating and preventing insulin resistance is a major focus of PCOS management.

Low-grade inflammation

Many women with PCOS have been found to have markers of low-grade chronic inflammation. This type of inflammation promotes insulin resistance and the production of androgens.

The source of this inflammation in PCOS is not definitively known, but may be related to:

  • Obesity and excess belly fat
  • High blood sugar levels
  • Abnormal ovarian function
  • Excess androgens

Anti-inflammatory treatments are being studied as potential therapies for PCOS.

Hormonal imbalances

PCOS involves several disturbances in normal hormone regulation:

  • Elevated luteinizing hormone (LH). This pituitary hormone stimulates ovulation as well as androgen production. Women with PCOS tend to have a high LH to follicle-stimulating hormone (FSH) ratio.
  • Prolactin excess in some women, which exacerbates problems with ovulation and menstrual cycles.
  • Low progesterone due to lack of ovulation.
  • Insufficient follicle development and selection in the ovaries.

These hormonal issues interfere with normal ovulation and menstruation.

Genetic factors

PCOS has a significant genetic component, as evidenced by the following:

  • Over 50 genes have been associated with susceptibility to PCOS.
  • Women with PCOS are more likely to have a sister or mother with PCOS.
  • Twin studies show that genetics account for 70% of the chance of developing PCOS.

While the exact genes involved are still under investigation, it is clear that genetic predisposition contributes significantly to PCOS risk.

How is PCOS diagnosed?

Since there are no single definitive tests for PCOS, diagnosis relies on a combination of clinical features and exclusion of other possible disorders. Some general diagnostic guidelines include:

Medical history

The physician takes a full medical history, asking about:

  • Menstrual cycle patterns since first period
  • Reproductive health issues
  • Symptoms of hyperandrogenism
  • Other health conditions
  • Family history of PCOS or related conditions

This helps identify the key PCOS features.

Physical exam

The physical exam assesses:

  • Signs of hyperandrogenism (hirsutism, acne, male-pattern balding)
  • Blood pressure, weight, waist circumference
  • Signs of insulin resistance

Lab testing

Common lab tests include:

  • Hormone levels – testosterone, androstenedione, prolactin, FSH, LH.
  • Glucose and insulin levels, particularly after a glucose challenge test.
  • Lipid profile.
  • Markers of inflammation and cardiac risk.

These tests help confirm PCOS biomarkers and identify related health risks.

Pelvic ultrasound

An ultrasound is done to visualize the ovaries and look for the characteristic “string of pearls” appearance caused by many small ovarian follicles. This is not required but can help support the diagnosis.

Excluding other conditions

Differential diagnosis is important to rule out other causes of irregular periods, infertility, and androgen excess such as:

  • Non-classic congenital adrenal hyperplasia
  • Cushing’s syndrome
  • Androgen-secreting tumors
  • Thyroid disorders

Once other possible disorders have been excluded, a diagnosis of PCOS can be made in women with at least 2 out of 3 of the main PCOS features: irregular periods, hyperandrogenism, polycystic ovaries.

Complications and health risks

If left unmanaged, PCOS can lead to a number of health complications and long-term risks:


Because PCOS often causes irregular ovulation or anovulation, it is a common cause of infertility. Up to 80% of women with PCOS have difficulty getting pregnant.

Endometrial cancer

The excess estrogen production that occurs when ovulation is irregular can cause overgrowth of the endometrium. This raises endometrial cancer risk 2-6 fold in women with PCOS.

Metabolic syndrome

Metabolic syndrome refers to a cluster of conditions that raise risk for cardiovascular disease and diabetes. These include:

  • Insulin resistance
  • High blood sugar
  • Excess visceral fat
  • High blood pressure
  • Abnormal cholesterol and triglycerides

Up to 80% of women with PCOS show signs of metabolic syndrome.

Type 2 diabetes

Insulin resistance combined with obesity significantly increase the chances of developing type 2 diabetes. Women with PCOS are 2-4 times more likely to develop diabetes than women without PCOS.

Heart disease

The metabolic abnormalities of PCOS raise the risks for heart attack, stroke, and other forms of cardiovascular disease. Women with PCOS have a 2-4 fold increased risk of heart disease compared to women without PCOS.

Mental health issues

PCOS symptoms like excess hair growth, acne, and infertility can negatively impact a woman’s self-esteem and quality of life. Women with PCOS have higher rates of depression, anxiety, eating disorders, and other mental health concerns.

What is the treatment for PCOS?

While there is no cure for PCOS, various treatments can help manage symptoms and reduce long-term health risks. Typical treatment approaches include:

Lifestyle modifications

Losing weight through diet and exercise is considered first-line treatment for PCOS. Even a 5-10% weight loss can help regulate menstrual cycles and lower androgen levels. A healthy low-glycemic diet and regular activity are encouraged.

Birth control pills

Oral contraceptives can help induce regular periods, correct hormonal imbalances, and reduce risks of endometrial overgrowth. Popular options contain ethinyl estradiol plus anti-androgenic progestins like drospirenone or norethindrone.

Ovulation induction agents

Medications like clomiphene and letrozole are used to induce ovulation in women with PCOS trying to conceive. Timed intercourse or ART procedures may be used in conjunction to optimize fertility.

Insulin-sensitizing drugs

Metformin and other insulin-sensitizing drugs treat insulin resistance and may help restore normal ovulation and menses. These drugs can aid weight loss efforts and reduce metabolic complications.


Drugs like spironolactone and finasteride can be used short-term to treat symptoms related to excess androgens like hirsutism and hair loss. Their long-term use is limited by side effects.


Laparoscopic ovarian drilling is sometimes used to induce ovulation in infertile women who do not respond to other treatments. This procedure destroys part of the ovary to normalize androgen and hormone levels.

What is the outlook for women with PCOS?

With proper management and lifestyle changes, the prognosis for PCOS is generally very good. While symptoms can often be controlled, PCOS does require lifelong monitoring and care.

Key points about the long-term outlook:

  • PCOS is a chronic condition without a cure, but symptoms can be well-managed in most women.
  • Lifestyle interventions combined with medical therapy can regulate cycles and fertility in the majority of patients.
  • Persistent care is required to prevent metabolic complications like diabetes, heart disease, and cancer.
  • A multidisciplinary approach including psychological support often produces optimal results.
  • With individualized treatments tailored to symptoms and goals, women with PCOS can live full, active lives.

Ongoing research brings hope for improved therapies and better understanding of the disorder. Increased awareness and screening for PCOS will allow for earlier diagnosis and treatment in young women.


PCOS is a complex hormonal and metabolic disorder with a variety of symptoms and health implications. The three defining features of PCOS are irregular menstrual cycles, hyperandrogenism, and polycystic ovarian morphology. These result from underlying problems with hormone regulation, insulin sensitivity, inflammation, and genetic factors.

Timely diagnosis and individualized management strategies are crucial to controlling symptoms, boosting fertility, and preventing long-term complications. Lifestyle interventions combined with medications and mental health support enable most women with PCOS to regulate their cycles, conceive, and reduce their cardiometabolic risks. While lifelong care is required, the prognosis for women with PCOS is generally positive. Ongoing research promises to further improve quality of life and health outcomes in PCOS patients.