Sperm maturity and treatment choice of in vitro fertilization (IVF) or intracytoplasmic sperm injection: diminished sperm HspA2 chaperone levels predict IVF failure.

To reexamine whether low sperm HspA2 ratios (formerly sperm CK-M ratio) are predictive for failure to cause pregnancies by in vitro fertilization (IVF) and to explore whether there are other male or female factors that may be predictive for IVF pregnancy outcome. Retrospective, cohort study. University-based IVF program. In 119 IVF cycles, three patient groups were studied: 25 men had a <10% sperm HspA2 ratio and a lack of pregnancies (HS <10% group), 50 men had a >10% sperm HspA2 ratio and no pregnancies (HS >10%NP group), and another 44 couples had a >10% sperm HspA2 ratio but did achieve pregnancies (HS >10%P group). Sperm HspA2 ratio determinations within 1 year of the IVF cycles and analysis of male and female IVF cycle parameters. Sperm HspA2 ratio determinations within 1 year of the IVF cycles and analysis of male and female IVF cycle parameters. In the three groups, male and female ages, number and maturation level of oocytes, and morphology of embryos were similar. In the HS < 10% group, mean sperm concentration and motility were close to normal, the fertilization and cleavage rates were lower, and cycles without any oocyte fertilization were higher. These parameters were similar in the two HS > 10% groups. The receiver operating characteristic curve in men with sperm HspA2 ratios of <17% (diminished and borderline sperm maturity) provided a cutoff value of 10.84% HspA2 ratio with a 100% positive predictive value for failure to achieve pregnancy, whether the men were oligospermic or normospermic. HspA2 ratios of <10% in the diminished sperm maturity range predict the failure to cause pregnancies by IVF. Thus, IVF should be bypassed in favor of ICSI. The occurrence of pregnancy with ICSI depends on the maturity of sperm selected, and it may not be as likely as in other indications for ICSI.