In a similar study serum PRL levels were significantly higher in infertile women with stage III-IV endometriosis (28.9±2.1 ng/mL) than in healthy controls (13.2±2.1 ng/mL), but they did not detect a significant difference in PRL concentrations in peritoneal fluid or follicular fluid, between case and control groups (5). This evidence concerns the gene PRL and Infertility.