The impact of GnRH agonists in patients with endometriosis on prolactin and sex hormone levels: a pilot study

OBJECTIVE: Gonadotropin releasing hormone agonists (GnRHa) decrease the expression of growth factors involved in the development of human endometriotic tissue. As endometriosis has been found to be associated with a mild increase in prolactin (PRL) serum levels, we aimed to evaluate changes in PRL serum levels as well as other hormones relevant to endometriosis and infertility during long-term administration of GnRHas in women with endometriosis. STUDY DESIGN: In this prospective pilot study we obtained blood samples on the first day of leuporeline administration and then subsequently after 4, 8 and 12 weeks in 22 patients. RESULTS: Median PRL levels were unchanged after 4 weeks, but significantly decreased 8 and 12 weeks after the first leuporeline administration (p1=0.085, p2=0.020, p3=0.001). There was no significant decrease in serum anti-Mullerian hormone (AMH) levels over the whole period of down regulation with leuporeline (p1-3>0.05). CONCLUSION: Our data support the hypothesis that the decrease of PRL levels might contribute to the known effect of GnRH treatment in patients with endometriosis via suppression of VEGF expression in endometriotic lesions. Moreover this study lends support to the thesis that AMH remains stable under GnRHa therapy and therefore can be also used as a marker of ovarian function prior to IVF-stimulation during down regulation.