Endometriosis and infertility: raised iron concentration in the peritoneal fluid and its effect on the acrosome reaction.

Endometriosis and infertility are commonly associated. This study investigated the role of accelerated lipid peroxidation of spermatozoa by the peritoneal fluid of patients with endometriosis as a cause for this association. It proposes that the increased iron concentration present in the fluid of these patients acts as a catalyst for the process. Peritoneal fluid from 25 patients with endometriosis and 25 matched controls was obtained at laparoscopy. Spermatozoa were incubated in the fluid from both groups and the subsequent acrosome reaction rates analysed. The relationship between these results and iron concentration in the fluid was examined. A significant decrease in the acrosome reaction rate was seen in the endometriotic group (P = 0.034). Overall, a decrease in the acrosome reaction rate was associated with an increased iron concentration in the fluid (18 of the 25 pairs). In mild disease, (six of 11 pairs), the relationship was not as marked as that in severe disease (12 of 14 pairs). These results suggest that the peritoneal fluid in patients with endometriosis has a detrimental action on the acrosome reaction of spermatozoa in vitro.