40w LaterGuide

Polycystic ovary syndrome (PCOS) is a common hormonal and metabolic condition that can affect menstrual cycles, ovulation, fertility, and long-term health. It affects around 10–13% of women of reproductive age worldwide, although symptoms can vary considerably from person to person.

What is PCOS?

PCOS is not simply a condition in which there are “many cysts” in the ovaries. It is a complex condition that can involve irregular or absent ovulation, higher levels or effects of androgens, and characteristic changes in the ovaries.

People with PCOS may experience irregular or infrequent periods, difficulty predicting ovulation, acne, increased facial or body hair, or difficulty becoming pregnant. Some people have only a few symptoms.

PCOS is also associated with an increased risk of metabolic conditions such as insulin resistance, type 2 diabetes, abnormal cholesterol levels, and cardiovascular risk factors.

How is PCOS diagnosed?

In adults, PCOS is generally diagnosed after other possible causes have been excluded and at least two of the following are present:

• Irregular or absent ovulation
• Clinical or biochemical signs of excess androgens
• Polycystic ovarian morphology identified by ultrasound or, in appropriate adults, AMH used according to current diagnostic guidance

If both irregular menstrual cycles and hyperandrogenism are present, an ultrasound or AMH test may not be necessary to make the diagnosis.

Importantly, having polycystic-appearing ovaries on an ultrasound does not by itself mean that you have PCOS.

Why can PCOS cause irregular periods?

With PCOS, ovulation may occur less frequently or may not occur in some cycles. This can lead to long or unpredictable menstrual cycles and sometimes abnormal uterine bleeding.

When ovulation occurs infrequently for a prolonged period, the endometrium may be exposed to estrogen without regular progesterone exposure. Over time, this can increase the risk of endometrial hyperplasia and endometrial cancer.

However, the overall chance of developing endometrial cancer remains low, and routine screening for endometrial cancer is not recommended solely because someone has PCOS. Long periods without menstruation or unusual bleeding should instead be discussed with a healthcare professional.

What does androgen excess mean?

Androgens are hormones that are present in everyone but may be higher or have stronger effects in some people with PCOS.

Signs can include increased facial or body hair, acne, or scalp hair thinning. Blood tests may also be used to evaluate androgen levels when appropriate.

Because normal hair growth and androgen levels differ by ethnicity and individual characteristics, these findings should be assessed in the appropriate clinical context.

What about insulin resistance?

Insulin resistance is an important feature of PCOS in many people. It can contribute to metabolic problems and is one reason people with PCOS have an increased risk of impaired glucose tolerance and type 2 diabetes.

PCOS does not mean that you will necessarily develop diabetes. Healthcare professionals may recommend assessment of blood glucose and other metabolic risk factors depending on your individual circumstances.

Is PCOS diagnosed differently in adolescents?

Yes. Irregular periods, acne, and changes in the ovaries can be part of normal puberty, making PCOS more difficult to diagnose during adolescence.

Current international guidance requires both persistent menstrual irregularity appropriate to the time since the first period and clinical or biochemical hyperandrogenism, after excluding other possible causes.

Ultrasound findings and AMH are not recommended for diagnosing PCOS in adolescents because they can lead to overdiagnosis.

Does PCOS mean I cannot become pregnant?

No. PCOS can make pregnancy more difficult when ovulation is irregular, but many people with PCOS become pregnant naturally or with treatment.

If you have very irregular or absent periods, are having difficulty becoming pregnant, or have symptoms that may suggest PCOS, talk with a healthcare professional for an appropriate evaluation.