Efficacy of the sperm survival test for the prediction of oocyte fertilization in culture

JG Franco Jr, AL Mauri, CG Petersen, RL Baruffi, MS Campos and JB Oliveira

Centro de Reproducao Humana Sinha Junqueira, Ribeirao Preto, Sao Paulo, Brazil.

The present study was carried out to investigate the predictive value of the sperm survival test (SST) with respect to the fertilization of oocytes in culture. In general, our laboratory uses a total of 50,000- 150,000 motile spermatozoa to inseminate each oocyte. The remaining material is evaluated for motility before and after 24 h of incubation at 37 degrees C in a 5% CO2 atmosphere. A total of 250 oocytes from 50 cases (mean +/- SD, 5.0 +/- 2.4 oocytes per retrieval) were inseminated and the final rate of cleaved embryos obtained was 52.5%. The SST (%) was considered normal when the ratio (final density of progressing spermatozoa after 24 h x 100/initial density of progressing spermatozoa) was 50% or more. Any other result was considered abnormal. Cases presenting one or more cleaved embryos (n = 40) were separated from those in which no embryo formation occurred (n = 10) and the results were compared in terms of the respective sperm survival rates over a period of 24 h: normal SST (one or more cleaved embryos, 37; none, five), abnormal SST (one or more cleaved embryos, three; none, five). The specificity of the SST was 0.92 and sensitivity 0.50, the predictive value of the abnormal test was 0.62 and the predictive value of the normal test 0.88. The efficacy of the test was estimated at 0.71, which was better than the conventional parameters of sperm analysis. A receiver-operating characteristics curve for SST confirmed that the test can be useful for the prediction of fertilizability of oocytes in the laboratory.

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