Increased pregnancy-associated plasma protein-A (PAPP-A) concentrations in peritoneal fluid of women with endometriosis

PROBLEM: Pregnancy-associated plasma protein-A (PAPP-A) belongs to a group of glycoproteins isolated from extracts of human placenta. Healthy ovarian and uterine tissues are also known to express PAPP-A. We hypothesized that PAPP-A levels might also be elevated in the peritoneal fluid (PF) of women with endometriosis, and examined variations in PF PAPP-A during the menstrual cycle and with the severity of the disease. METHOD OF STUDY: PF PAPP-A were measured in 60 women with endometriosis and 38 women without endometriosis using a high-sensitivity immunofluorometric assay. RESULTS: We found that the mean level of PAPP-A was higher in PF from patients with endometriosis than controls (p = 0.003). Furthermore, significant correlation was found between the stages of endometriosis and the levels of PAPP-A in these patients (r = 0.39, p = 0.009). The concentrations of PAPP-A in PF were significantly higher in the secretory phase than the proliferative phase of the menstrual cycle in both women with and without endometriosis (p = 0.009 and P = 0.002, respectively). Finally, among the controls, women undergoing tubal ligation had significantly lower mean PF levels of PAPP-A than women with infertility or pelvic pain (P = 0.001). CONCLUSION: We conclude that PF levels of PAPP-A vary during the menstrual cycle, and are highest in the secretory phase. We also find that PF PAPP-A levels are significantly increased in women with endometriosis, and that the degree of elevation corresponds to the extent of disease.