Relationship between sexual abstinence duration and the acrosome index in teratozoospermic semen: analysis of 1800 semen samples.

A high acrosome index (percentage of sperm with normal acrosome morphology--cutoff value > or =10%) is known to be associated with an improved fertilization rate in conventional IVF. A retrospective evaluation of the relationship between duration of sexual abstinence and acrosome index among oligozoospermic and normozoospermic semen samples with teratozoospermia was undertaken. A significant (P = 0.001) decrease in the acrosome index was observed among the normozoospermic samples (n = 1264) between the peak value of 10.2 +/- 3.6% on day 2 and 8.5 +/- 4.0% on day 5 of abstinence, while for the oligozoospermic samples (n = 536) the peak value of 8.7 +/- 3.5% was observed on day 1 and the lowest values of 6.8 +/- 3.7% (P = 0.04) on day 5 of abstinence. The results suggest that an optimal acrosome index will be obtained following a short sexual abstinence.