Macroprolactinemia in hyperprolactinemic infertile women.

Hyperprolactinemia occurs in 15-20 % of women with menstrual disturbances and 30-40 % of infertile women and it can adversely affect the fertility. High molecular weight prolactin (macroprolactin) has long been known in hyperprolactinemic fertile women. However, the prevalence of macroprolactinemia in hyperprolactinemic infertile women is not known. This cross-sectional study was carried out during the period of June 2010 and June 2011 at a single tertiary care centre. All women who attended the infertility clinic during this period were screened for hyperprolactinemia and only women with hyperprolactinemia and infertility were further studied for the presence of macroprolactin by polyethylene glycol precipitation assay. We compared the clinical, hormonal profile and fertility outcome of infertile women with true hyperprolactinemia and macroprolacinemia using appropriate statistical tests. Of 1,163 infertile women, 183 (15.7 %) had hyperprolactinemia [134 (73 %) had primary infertility and 49 (27 %) had secondary infertility]. Out of these 183 women with hyperprolactinemia, one had microadenoma, 161 had true idiopathic hyperprolactinemia and 21 (11.5 %) women had macroprolactinemia. The prevalence of oligomenorrhea and galactorrhea were significantly higher in patients with true hyperprolactinemia than macroprolactinemia (46 vs. 14 %, p < 0.008 and 30 vs. 5 %, p = 0.01 respectively). Twenty-two patients (13.5 %) of true hyperprolactinemia and two (9 %) in macroprolactinemia became pregnant during the study period. Prolactin measurement should be a part of routine evaluation of couples referred to infertility clinics. Macroprolactin screening is mandatory when clinical features and serum PRL assay results are conflicting. Patients with macroprolactinemia should be investigated for causes of infertility other than hyperprolactinemia.