IntroductionThe dynamics of sperm DNA fragmentation (SDF) using the semen samples before and after capacitation have been investigated in a prospective study. All samples were processed with Halosperm for the SDF analysis. ObjectiveThe experimental design had as its aim to analyse the effect of seminal plasma on the SDF and the hypothesis was that the differences in the dynamics of the SDF would be greater in semen samples prior to capacitation due to the physiological conditions of the seminal plasma being different between individuals. Material and methodsHowever, after capacitation, the rate of increase of SDF would be more homogeneous due to the sperm storage conditions. Sperm from 5 donors was incubated for a period of 72 hours in the seminal plasma itself or in the appropriate diluent after capacitation and the SDF rates were measured after different incubation times (from 0 to 72h). The dynamic behaviour of the SDF before capacitation gave R2 values higher than those obtained after capacitation. According to our hypothesis seminal plasma appears to play an important role in controlling the dynamics of sperm DNA fragmentation, since a more homogeneous tendency for SDF to increase was observed after plasma removal. Results and discussionAlthough preliminary, the results do indicate that both the management and capacitation of human sperm for use in assisted reproduction techniques must be completed quickly in order to minimise the DNA damage, this practice should theoretically result in improved pregnancy rates.