Value of the hamster oocyte test and computerised measurements of sperm motility in predicting if four or more viable embryos will be obtained in an IVF cycle

The experimental group consisted of men from 81 couples waiting for in vitr o fertilization (IVF), about half of whom had sperm dysfunction defined by a negative post-coital test. A diagnostic semen sample was subjected to a h amster oocyte penetration test (HOPT) after stimulation of the acrosome rea ction with A23187 +/- pentoxifylline and to computerized sperm motility mea surements (CASA) as well as conventional semen analysis according to the WH O protocol. Logistic regression was used to identify parameters that predic ted the probability of achieving four or more viable embryos at IVF among t he 65 couples from whom four or more oocytes were collected. The number of oocytes available and whether the woman had previously been pregnant (ever pregnant) were important factors but once these had been taken into account a number of sperm parameters had additional predictive power. The most use ful of these were the percentage sperm static (CASA) or the percent sperm p rogressively motile (conventional semen analysis) in the Percoll preparatio n. A model incorporating the number of oocytes collected, ever pregnant and percentage sperm static achieved 85% correct prediction of outcome in the experimental dataset but only 62% correct prediction in an independent set of 280 IVF cycles. The percentage of hamster oocytes penetrated was a signi ficant predictor but had no advantage over simple motility measurements. Th e results illustrate the difficulty of basing a prognosis for achieving sat isfactory fertilization in IVF on the properties of spermatozoa.