PCOS Explained: Rotterdam Criteria and the Right Therapy for Your Goal

At a glance

What is it? A common hormonal condition with a disturbed cycle, signs of male hormones and often many follicles.
How common? About one in ten women of childbearing age.
Diagnosis Via the Rotterdam criteria: two of three points, with other causes excluded.
In the background Often an insulin resistance.
Treatment Depends on the goal (trying to conceive or not); the basis is lifestyle.
ICD-10 E28.2 (polycystic ovary syndrome)

What is PCOS?

PCOS stands for polycystic ovary syndrome. It is one of the most common hormonal conditions in women of childbearing age, affecting about one in ten. PCOS typically brings three things together: a disturbed cycle with irregular ovulation, signs of too many male hormones and often, but not always, many small follicles in the ovaries.

An insulin resistance is frequently present as well. PCOS can be treated well, even though it is not curable so far. Important: despite the name, the “cysts” are not dangerous growths but immature follicles.

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Symptoms

PCOS shows itself in very different ways. Typical signs are:

  • an irregular cycle: infrequent, very long or absent periods.
  • an unfulfilled wish to have children, because ovulation does not happen.
  • signs of too many male hormones: excess body hair (for example on the face), acne or oily skin.
  • hair loss on the scalp in a male pattern. More on this: Hair loss.
  • weight gain or difficulty losing weight, often around the belly. More on this: Obesity.

Not every woman has all signs, and the severity ranges from barely noticeable to very distressing.

Causes and the role of insulin resistance

Why PCOS develops is not fully understood. Several factors act together, often with a family predisposition. For many of those affected, insulin resistance plays a central role: the body responds less well to the hormone insulin, the insulin level rises, and this can stimulate the ovaries to produce more male hormones and disturb ovulation.

This connection explains why excess weight can intensify PCOS and why losing weight and medicines such as metformin can help. Important: PCOS also affects slim women, and no one is to blame for the condition.

The Rotterdam criteria: how PCOS is determined

PCOS is not determined by a single test, but via the so-called Rotterdam criteria. According to these, in adults PCOS is present when at least two of three points are met and other causes have been excluded:

  1. a disturbed cycle: infrequent, irregular or absent ovulation, often recognisable from irregular or absent periods.
  2. signs of too many male hormones (androgens): either visible (excess body hair, acne, scalp hair loss) or measurable in the blood.
  3. polycystic ovaries: many small follicles on ultrasound. In adults, a blood test can be used instead of ultrasound, the anti-Müllerian hormone (AMH).

Important: only two of the three points need to apply. So you do not necessarily need “cysts” to have PCOS, and conversely a few follicles on ultrasound alone do not mean PCOS. Which combination is present results in the so-called phenotype (type A to D), which co-determines which risks and which treatment are in the foreground.

A common misconception The “cysts” in the name are not true cysts but immature follicles. Before the diagnosis, the doctor rules out other causes, for example a thyroid or other hormone disorder. In very young women and adolescents, stricter rules apply, and ultrasound is not yet used here.

Treatment by goal: trying to conceive or not?

There is no one-size-fits-all treatment for PCOS. What makes sense depends above all on one question: is there a current wish to have children or not? One thing, however, applies to everyone.

The basis for everyone. A healthy lifestyle is the most effective foundation. Even a modest weight loss of about 5 to 10 percent can clearly improve the cycle, ovulation and symptoms if you are overweight. Exercise and a balanced diet also help independently of weight.

Without a current wish to have children. Here the aim is to regulate the cycle, protect the lining of the womb and ease androgenic symptoms such as acne or excess hair. For this, above all the pill (combined hormonal preparations), if needed anti-androgenic medicines, and depending on the metabolic situation metformin come into question. More on this in the next section.

With a wish to have children. Here ovulation is the focus. Often weight optimisation alone helps. If that is not enough, ovulation can be stimulated with medication, today usually with the active substance letrozole as first choice (off-label in Germany), sometimes in combination with metformin. The pill is of course not an option here, since it prevents pregnancy. Fertility treatment belongs in specialist hands.

Metformin or the pill? An honest weigh-up

Many people ask this question, and the honest answer is: it depends on your goal. Metformin and the pill serve different purposes and are not a simple either-or.

The pill (combined hormonal preparations) Metformin
Mainly for regulates the cycle, protects the lining of the womb, eases androgenic symptoms (acne, excess hair) acts on insulin resistance, can favourably influence metabolism and weight, sometimes more regular cycles
When trying to conceive not suitable, as it prevents pregnancy possible, sometimes used to support ovulation and metabolism (off-label in Germany)
Downsides and side effects its own risks (for example thrombosis) and contraindications; does not act directly on insulin resistance above all gastrointestinal symptoms at the start; not a contraceptive; does not act directly on skin and hair
Often sensible when there is no wish to have children and androgenic symptoms are in the foreground there is a clear insulin resistance or metabolic problems, often as an addition

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In short: if there is no wish to have children and you are mainly bothered by your cycle, acne or excess hair, the pill is often the first choice, also because it protects the lining of the womb. If it is more about metabolism, insulin resistance or a wish to have children, metformin plays to its strengths. A combination is often sensible too. What suits you best you decide together with your doctor, depending on your goal, symptoms and metabolic situation.

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When to see a doctor

An appointment at a gynaecology practice is sensible if your cycle is irregular or absent over a longer period, if signs of too many male hormones appear (excess hair, acne, hair loss) or if a wish to have children is not being fulfilled. An early work-up helps to ease symptoms and keep an eye on long-term risks.

More than just the cycle PCOS is also a metabolic matter. In the long term, regular checks of blood sugar and weight are part of it, because the risk of type 2 diabetes is increased. A cycle that is absent for a long time should not simply be ignored, because the lining of the womb needs protection. And PCOS can also be a psychological strain: low mood or worries about appearance and about having children are common and to be taken seriously. You do not have to deal with this alone.

Stay on top of your PCOS therapy with brite

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  • Interaction check: see at a glance whether your medicines work well together.
  • Medication plan: all medicines in one place, ready for the next appointment.
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Frequently asked questions

The criteria by which PCOS is determined. At least two of three points must be met: a disturbed cycle, signs of too many male hormones and polycystic ovaries on ultrasound (or a raised AMH). Other causes must be excluded.

No. Two of the three criteria are enough. Besides, the “cysts” are not true cysts but immature follicles. Some women have PCOS without notable ovaries on ultrasound.

PCOS cannot be fully cured so far. But it can be treated well, and many symptoms improve clearly, for example through lifestyle, the right medication and targeted therapy.

Yes. PCOS is a common cause of an unfulfilled wish to have children, but many women do get pregnant, often after weight optimisation and, if needed, with medication to support ovulation.

It depends on the goal. The pill regulates the cycle and eases androgenic symptoms when there is no wish to have children. Metformin acts on insulin resistance and is compatible with a wish to have children. Sometimes they are combined.

Yes. Even a modest weight loss of about 5 to 10 percent can clearly improve the cycle, ovulation and symptoms if you are overweight. Exercise also helps independently of weight.

No. PCOS also affects slim women. Excess weight can intensify the symptoms, but it is not a precondition for the condition.

Above all an increased risk of type 2 diabetes and metabolic problems. With a cycle that is absent for a long time, the lining of the womb needs protection. Regular medical check-ups are therefore sensible.

Related topics

Quellen

  1. Monash University, ESHRE und ASRM: International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome (2023). monash.edu/medicine/mchri/pcos/guideline
  2. DGGG: S2k-Leitlinie „Diagnostik und Therapie des polyzystischen Ovarsyndroms (PCOS)“ (AWMF). register.awmf.org
  3. IQWiG / gesundheitsinformation.de: Polyzystisches Ovarialsyndrom (PCOS). gesundheitsinformation.de
  4. Frauenärzte im Netz (BVF und DGGG): Patienteninformationen zu PCOS. frauenaerzte-im-netz.de
  5. ESHRE: Patienteninformationen zum polyzystischen Ovarialsyndrom. eshre.eu
Important note: This article is for general information and does not replace medical advice, diagnosis or treatment. Which work-up and treatment are right for you depends on your individual situation and your goal and belongs in medical (gynaecological) hands. Last updated: June 2026.