High plasma concentrations of di-(2-ethylhexyl)-phthalate in women with endometriosis

BACKGROUND: Emerging evidence suggests a potential role for ubiquitous environmental contaminants in the physiopathology of endometriosis. Di-(2-ethylhexyl)-phthalate (DEHP), the most commonly used plasticizer in flexible polyvinylchloride (PVC) formulations, is a widespread environmental contaminant with potentially adverse effects on fertility in animal models. In the present study, we tested the hypothesis that DEHP and/or and its main metabolite, mono-ethylhexyl phthalate (MEHP), play a role in the pathogenesis of endometriosis. METHODS: Specimens of blood and peritoneal fluid were collected in a group of women with endometriosis (n = 55), and in age-matched control women (n = 24). Concentrations of DEHP and MEHP were measured in plasma and peritoneal fluid by using high performance liquid chromatography (HPLC). Differences between groups were tested using the Fisher's exact test, Wilcoxon-test, and Kruskal-Wallis analysis of variance. RESULTS: Endometriotic women showed significantly higher plasma DEHP concentrations than controls (median 0.57 mug/ml, interquartile range: 0.06-1.23; values range: 0-3.24 versus median 0.18 mug/ml, interquartile range: 0-0.44; values range: 0-1.03; P = 0.0047) and 92.6% of them had detectable DEHP and/or MEHP in the peritoneal fluid. No significant differences in either the DEHP/MEHP plasma concentrations (P greater than or equal to 0.31) or DEHP/MEHP peritoneal fluid concentrations (P greater than or equal to 0.66) were observed in the endometriotic patients as a function of the disease stage at the time of diagnosis. CONCLUSIONS: The present findings showed for the first time an association between DEHP plasma concentrations and endometriosis, suggesting a possible role for phthalate esters in the pathogenesis.