Endocrine Abstracts

Introduction: Hyperprolactinemia (HP) is a common disorder in endocrinology. Based on the various etiology, HP could be divided into: physiological, pathological, drug-induced and idiopathic HP. Regardless of its origin, HP usually affects reproductive endocrine axis. The aim of the study was to determine differences in menstrual cycle abnormalities in patients with different causes of hyperprolactinemia.

Patients and methods: The study included 81 patients with HP, divided into the following groups: pathological HP (PTHP, 29 patients), drug-induced HP (DIHP, 27 patients) and idiopathic HP (IHP, 25 patients). Following diagnostic procedures were performed: clinical examination, detailed drug history, biochemical investigation and radiological imaging. Hormonal testing included prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E2), progesterone, testosterone, thyroid stimulating hormone (TSH) and free thyroxin (FT4), cortisol and adrenocorticotropic hormone (ACTH).

Results: PRL concentrations were significantly higher in PTHP and DIHP compared to IHP. The youngest patients were with IHP, followed by PTHP and DIHP. Among PTHP majority of the patients had oligomenorrhea (37.9%) followed by polymenorrhea (20.7%). Regular cycle length with absence of ovulation and amenorrhea was verified in the same number of patients (13.8% each). Two women were in menopause (6.9%) and two were with completely regular cycle (6.9%). The highest number of the patients with DIHP had amenorrhea (37%) and oligomenorrhea (22.2%), followed by polymenorrhea and menopause (14.8%, each). Only two patients had regular cycle (7.4%) and one regular cycle without ovulation (3.7%). In the group of patients with IHP, majority had regular cycle (44%) and regular cycle without ovulation (24%), followed by polymenorrhea (16%) and oligomenorrhea (12%). Only one patient had amenorrhea (4%) and none menopause. Normalization of the prolactin concentration after discontinuation of the drugs which caused HP/ or after dopamine agonist treatment, resulted in the significant decrease in menstrual cycle abnormalities in all study groups.

Conclusion: Majority of patients with highest PRL levels (PTHP and DIHP) had oligomenorrhea and amenorrhea, while patients with less increased PRL concentrations (IHP) rarely had this type of abnormalities. Even though different etiology of hyperprolactinemia can cause different menstrual disorders, the main factor which will determine severity of these abnormalities is the level of PRL concentration.