Does Endometriosis Affect PAPP-A Concentration in First Trimester Fetal Screening Test?

Abstract

Objective Pregnancy-associated plasma protein A (PAPP-A) is a macromolecular glycoprotein. The peritoneal fluid of women affected by endometriosis shows a significant increase of PAPP-A levels. Given the important role of PAPP-A in first trimester screening test, we wondered if its presence in the peritoneal fluid of women with endometriosis could affect biochemical parameters of the test performed during pregnancy. Methods A prospective study enrolled 78 women with singleton pregnancy who performed combined test between 11 + 0 and 13 + 6 weeks of gestation: 25 women with previous histological diagnosis of endometriosis and 53 women without. All patients were sampled to determine PAPP-A concentrations. Serum levels of PAPP-A were expressed in UI/L and in MoM (multiples of median). The two groups – endometriosis women and non-endometriosis women – were compared in order to find a possible different concentration of serum PAPP-A. Results We found an increased concentration of both PAPP-A UI/L and PAPP-A MoM in deep endometriosis patients versus ovarian endometriosis with significant difference in PAPP-A MoM (p = 0.018). We also found a significant association between the stage of the disease and PAPP-A UI/L and MoM levels (PAPP-A UI/L p = 0.05, PAPP-A MoM p = 0.01). Conclusions Women with deep endometriosis show increased serum PAPP-A concentrations compared to women with ovarian endometriosis. Likewise, women with moderate or severe stage of the disease show increased serum PAPP-A concentrations compared to women with minimum or mild disease. This increase could affect first trimester aneuploidy screening test and endometriosis could represent a confounding factor in the calculation of aneuploidy risk.