OBJECTIVETo investigate the role of nitric oxide (NO) in the pathogenesis of early endometriosis-associated infertility.

METHODSThe volume of peritoneal fluids was recorded and the concentration of NO in peritoneal fluid and serum was measured with a fluorescence method using 4, 5-diaminofluorescein (DAF-2) as an indicator, in 60 patients with early endometriosis-associated infertility ( endometriosis group), 60 patients with tubal infertility (tubal infertility group) and 20 patients without infertility (control group). The IVF-ET outcomes between patients with endometriosis and tubal infertility were compared.

RESULTThe volume of peritoneal fluids from endometriosis group patients increased significantly compared with that in tubal infertility group patients and control groups. The concentration of NO in peritoneal fluid of the control group,the tubal infertility group and the endometriosis group was 9.98, 13.76 and 20.72, respectively (P<0.017). Furthermore the concentration of NO in serum of the patients of control group,tubal infertility group and endometriosis group was 12.25, 13.00, 13.60, respectively; there were no significant differences among these three groups. There were no significant differences in implantation rate, pregnancy rate and abortion rate of IVF-ET between endometriosis group patients and tubal infertility group patients. However, the fertilization rate was significantly lower in endometriosis group patients than that in tubal infertility group patients.

CONCLUSIONChanges of nitric oxide in peritoneal fluids may play an important role in the pathogenesis of early endometriosis-associated infertility and IVF-ET may serve as an alternative method for this type of infertility.