Many believe irregular periods are essential for diagnosing polycystic ovary syndrome (PCOS), but this is not always the case. According to the ‘Rotterdam’ criteria, PCOS is diagnosed when any two of three features are present: 1) Hyperandrogenism – excess androgens, 2) irregular or absent ovulation, 3) polycystic ovaries on ultrasound. This means that even if a girl has regular menstrual cycles, she can still have PCOS if she shows signs of hyperandrogenism and polycystic ovaries, or if ovulatory dysfunction is confirmed through hormonal testing.

When Periods are Regular but PCOS is Present: 

For instance, signs of hyperandrogenism, such as acne or hirsutism, along with polycystic ovarian morphology on ultrasound, may fulfil diagnostic standards. It is also important to understand that ovulatory dysfunction may be “silent”. A regular period does not guarantee ovulation. Progesterone testing in the mid-luteal phase often reveals whether ovulation is occurring. Some women with regular periods nonetheless experience chronic anovulation.

PCOS Diagnosis in Adolescents: 

A Nuanced Approach: In adolescent girls, diagnosing PCOS is more nuanced. During puberty, menstrual irregularity is common, and current guidelines suggest waiting two years post-menarche before diagnosing PCOS. In teens, both persistent hyperandrogenism and irregular cycles are typically required. If only high androgens are present alongside regular periods, the diagnosis is deferred, but they are considered “at risk” and are monitored over time.

Lifestyle and Management Strategies: 

When managing PCOS, lifestyle modifications are necessary. A nutrient-rich diet is essential. Low-glycaemic, whole foods, including vegetables, whole grains, legumes, nuts, healthy fats, and lean protein, while limiting added sugars and processed foods, have been shown to reduce insulin resistance and inflammation. Regular exercise, both aerobic and resistance training, improves insulin sensitivity, aids weight management, and helps regulate reproductive hormones. 

Mental Health:

The Overlooked Dimensions: Mental health support is also crucial, as PCOS is associated with higher rates of anxiety and depression, sometimes regardless of menstrual status. Psychological well-being must be monitored and addressed as part of comprehensive care. 
 

Conclusion:

Irregular periods are common in PCOS but not mandatory. Girls and women with normal cycles can still have PCOS if they meet two of the three Rotterdam criteria, particularly hyperandrogenism and polycystic ovaries or hyperandrogenism and demonstrable anovulation. In teenagers, both irregular cycles and hyperandrogenism are typically required to confirm a diagnosis. If someone shows signs like acne or excess hair along with polycystic ovaries, even with regular periods, PCOS should be considered and evaluated appropriately. Clinical judgement guided by established diagnostic criteria is essential to ensure accurate identification of PCOS, regardless of menstrual regularity.

Hema, is a Specialist Dietitian at The London Obesity & Endocrine Clinic. She has helped many patients overcome weight management barriers.