What is one of the Rotterdam criteria for diagnosing PCOS?

The Rotterdam criteria for diagnosing polycystic ovary syndrome (PCOS) require the presence of at least two of the following three features: irregular or absent menstrual cycles, clinical and/or biochemical signs of hyperandrogenism (such as hirsutism), and polycystic ovaries observed on ultrasound. The presence of hirsutism is significant because it reflects hyperandrogenism, which is a key aspect of the disorder. This symptom occurs due to an imbalance in sex hormones, leading to excess male hormone levels that can cause excessive hair growth in areas where men typically grow hair.

The other options listed do not align with the Rotterdam criteria. Regular menstrual cycles would actually be contrary to the typical presentation of PCOS, which often involves irregular cycles. While polycystic ovaries can be identified on ultrasound, reliance on CT scans is not standard practice for this diagnosis, as ultrasound is the preferred imaging method. Elevated thyroid hormone levels are not a criterion for diagnosing PCOS, as thyroid dysfunction is a separate condition and does not directly pertain to the characteristics defining PCOS. Therefore, the presence of hirsutism stands out as one of the key criteria for diagnosing PCOS.