OBJECTIVE: To develop a reliable sperm test that would predict pregnancy rate in assisted reproductive technologies. DESIGN: Blind prospective cohort study. SETTING: Tertiary-care, university hospital-affiliated IVF program. PATIENTS: One hundred nineteen sperm samples were obtained from 110 males from couples undergoing IVF or GIFT (ART). Sperm samples were washed by Percoll, incubated at 24 degrees C for 4 hours, and an aliquot of the same sperm suspension was used for ART incubated at 40 degrees C for 4 hours (stress test). Stress test scores are expressed as the ratio of final to initial motility. RESULTS: Of 119 ART cycles, 24 resulted in pregnancy. Of 24 pregnancies, 23 occurred in cycles that used sperm samples with stress test scores > or = 0.75 and only one with a stress test score < 0.75. The negative predictive value of the test, defined as the absence of pregnancy with scores < 0.75, was 98% and the positive predictive value, defined as the occurrence of pregnancy with scores > or = 0.75, was 36%. Logistic regression analysis indicated that the stress test score alone was correlated significantly with pregnancy after ART. CONCLUSION: These results indicate that stress test scores < 0.75 are predictive of poor pregnancy outcome in ART.
OBJECTIVE: To develop a reliable sperm test that would predict pregnancy rate in assisted reproductive technologies. DESIGN: Blind prospective cohort study. SETTING: Tertiary-care, university hospital-affiliated IVF program. PATIENTS: One hundred nineteen sperm samples were obtained from 110 males from couples undergoing IVF or GIFT (ART). Sperm samples were washed by Percoll, incubated at 24 degrees C for 4 hours, and an aliquot of the same sperm suspension was used for ART incubated at 40 degrees C for 4 hours (stress test). Stress test scores are expressed as the ratio of final to initial motility. RESULTS: Of 119 ART cycles, 24 resulted in pregnancy. Of 24 pregnancies, 23 occurred in cycles that used sperm samples with stress test scores > or = 0.75 and only one with a stress test score < 0.75. The negative predictive value of the test, defined as the absence of pregnancy with scores < 0.75, was 98% and the positive predictive value, defined as the occurrence of pregnancy with scores > or = 0.75, was 36%. Logistic regression analysis indicated that the stress test score alone was correlated significantly with pregnancy after ART. CONCLUSION: These results indicate that stress test scores < 0.75 are predictive of poor pregnancy outcome in ART.