¹D.B. Brown, ²B.J. Maeker, ³J. Meriano, ⁴R.F. Casper
Department of Human Biology, Chemistry and Genetics
University of Texas Medical Brnach, Galveston, TX 77555-0645
²Diagnostic System Laboratories, Inc, Webster, TX
³Toronto Centre for Advanced Reproductive Technology, Canada
⁴Department of Ob/Gyn, University of Toronto, Canada

In previous studies, sperm samples from 74 unexplained infertility patients whose sperm were normal in standard semen analysis, were analyzed in the human sperm activation assay (HSSA; Brown et al. Yale J Biol Med 1992;65:29; Fertil Steril 1995;64:612). Sixteen (21.6%) of the 74 inexplicably infertile males produced sperm that responded abnormally in the HSAA. Portions of the 16 samples were also used in ART attempts at pregnancy (IUI, IVF-ET, GIFT), none of which resulted in pergnancies. We have extended these studies by using the HSAA to analyze sperm samples from 23 males with either unexplained infertility or male factor infertility (other than abnormal morphology; see other Brown et al. Abstrat, this meeting); the 23 samples also used in ICSI attempts at pregnancy. Permeabilized human sperm were incubated in Xenopus laevis frog egg extract containing tritiated thymidine, and the % of sperm that decondensed their chromatin and synthesized their DNA during the 2 hour in vitro assay, were determined. All patient assays were performed in parallel with an assay using control sperm from a fertile male. An abnormal response was <90% of the control for decondensation and/or DNA synthesis. Six of the 23 samples responded abnormally in the HSAA, with ICSI fertilization and cleavage rates of 56.9% and 100% respectively. Five of the 6 abnormal HSAA responders (83%) had unsuccessful ICSI attempts at pregnancy. Seventeen of 23 samples responded normally in the HSAA, with ICSI fertilization and cleavage rates of 69.3% and 98%, respectively. Our criterion for determining pregnancy success is that the pregnancy must traverse the first trimester without a spontaneous abortion. The pregnancy rates of the normal HSAA responders are still being determined. In this study, a significant different in fertilization rates was observed (56.9% vs. 69.3%). Data from this and the previous studies indicate that the HSAA has utility in determining sperm sample efficacy for fertilization in ART attempts at pregnancy.