Objective: To determine if a human sperm activation assay can be used to evaluate males exhibiting otherwise unexplained infertility.
Design: Sperm from age-matched fertile and idiopathic infertile males were assayed in the human sperm activation assay and the results were compared. A portion of the sperm from the idiopathic infertile males also was used in assisted reproductive technology (ART) attempts at pregnancy.
Patients: Idiopathic infertile couples who had extensive fertility testing with no identified problems that would explain their infertility. Fertile males that had fathered one or more children.
Main outcome measures: Sperm nuclear decondensation-recondensation and DNA synthesis. Pregnancies resulting from ART using semen from a male whose sperm responded abnormally in the human sperm activation assay.
Results: Thirteen (22%) of 59 idiopathic infertile males produced sperm that responded abnormally in the human sperm activation assay. Only 1 (1.7%) of 59 fertile males produced sperm that responded abnormally in the human sperm activation assay. The percentage of abnormal responders in the patient group exhibiting unexplained infertility was significantly higher than in the fertile male group. No sperm samples that responded abnormally in the human sperm activation assay resulted in pregnancies when used in ART.
Conclusions: The human sperm activation assay is a new and independent indicator for some cases of infertility that otherwise would be unexplained. The human sperm activation assay appears to have utility in determining a sperm sample's efficacy for fertilization in ART attempts at pregnancy.