Endocrine Abstracts

Background: Hyperprolactinemia is frequently reported with polycystic ovary syndrome (PCOS). However, there is a controversy whether they share a common mechanism or have cause–result relationship or just are coincidental. The objective of the present study was to identify the cause of hyperprolactinemia in patients with PCOS.

Methods: We retrospectively evaluated our outpatient admission records for PCOS, hirsutism, oligomenorrhea, or secondary amenorrhea. PCOS diagnosis was made after excluding other causes of hirsutismus and in accordance with Rotterdam criteria. Patients to be included in the study required not to receive any medication for PCOS within the last 6 months. Fasting serum glucose, insulin, FSH, LH, total and free testosterone, DHEA-S and lipid profile were determined. If hyperprolactinemia was present, in the second step prolactin levels were determined by polyethyleneglycol (PEG) precipitation method, in order to exclude macroprolactinemia.

Results: During the study period, 117 women (median 24.5 years, range 16–40) was diagnosed with PCOS. The median prolactin level was 15.4 (normal value 6–30) ng/ml. Nineteen (16.2%) had elevated levels of prolactin (median 41, range 30.5–118.2 ng/ml). Two patients were receiving antipsychotics, and 3 were using antidepressants. Nine of the remaining 14 patients had mild hyperprolactinemia, and PEG precipitation method revealed normal prolactin levels. Pituitary MRI showed microadenoma in two, and pituitary gland heterogenity in other two patients. One patient was diagnosed with hypothyroidism and Hashimoto thyroiditis. In univariate analysis, the serum prolactin levels did not correlate with any of the the following parameters: HOMA-IR score, total testosteron, free testosteron, DHEA-S, LDL-C, HDL-C, triglyceride, LH or FSH.

Conclusions: Since hyperprolactinemia is not a clinical manifestation of PCOS, patients with increased PRL levels should be investigated for other causes of hyperprolactinemia.