Increased plasma levels of phthalate esters in women with advanced-stage endometriosis: a prospective case-control study.

We performed the present prospective case-control study to evaluate whether the plasma concentrations of phthalate esters are elevated in women with advanced-stage endometriosis in a Korean population. Measuring plasma levels of monoethylhexyl phthalate and di-(2-ethylhexyl) phthalate in 97 women with advanced-stage endometriosis and 169 control women by liquid chromatography-tandem mass spectrometry, we found that the concentrations of monoethylhexyl phthalate, as well as di-(2-ethylhexyl) phthalate, are significantly higher in those with advanced-stage endometriosis, which supports the hypothesis that exposure to phthalate might play a role in the establishment of endometriosis.