Endocrine Abstracts

Background: Polycystic ovarian syndrome (PCOS) diagnosis is set based on Rotterdam criteria, including hyperandrogenism, chronic anovulation and typical ultrasound appearance. 65–70% of women with PCOS have insulin resistance. Metformin, an oral antidiabetic agent, was the first drug used to treat insulin resistance in PCOS patients.

Material and method: Twenty non-diabetic women between 25–35 years old, with PCOS untreated prior to presentation, with a BMI>30 kg/m², were included in our study. Ovarian, thyroid ultrasound, BMI, TSH, fT4 levels were evaluated at baseline, at 3 and 6 months of treatement. All patients received metformin administered daily on a weekly increased dose up from 500 mg/day to a total of 2 g/day. 9 patients had subclinical hypothyroidism (SCH) (TSH levels 4.5–6 mUI/l). 11 patients were euthyroid. None of the patients had received levothyroxine treatment before the inclusion in our study. None of the patients were on a meat and dairy free diet.

Results: TSH levels decreased from a median of 4.9 mUI/ml at baseline to a 2.8 mUI/l after 3 month of treatment. Levothyroxine was added after 3 months of treatement in 4 of the patients (TSH>4.5 mUI/l). At 6 months all SCH patients had normal TSH levels (<3.1 mUI/l). No significant changes in TSH levels were noticed in euthyroid patients.

Conclusions: Metformin use induced an TSH lowering effect in obese patients with PCOS and SCH, reducing the need for levothyroxine replacement in selected patients.

Keywords: metformin, pcos, subclinical hypothyroidism.