ABSTRACT Introduction: D-Aspartate is an endogenous amino acid involved in LH and testosterone release in humans. In this study we investigate the impact of nutritional supplementation of sodium D-aspartate on the improvement of sperm quality in sub-fertile patients and the rate of pregnancies that occurred with their partners. Materials and Methods: A group of 30 patients affected by oligo-asthenozoospermia and a group of 30 patients affected by asthenozoospermia were treated with a daily dose of sodium D-aspartate for 90 days. After which, the change in spermatozoa concentration and their motility and the pregnancies that occurred with their partners were recorded. Results: We found that the supplementation of D-aspartate significantly increased the concentration and the motility of spermatozoa. In oligo- asthenozoospermic patients the increase of sperm concentration was found to be 2.0-fold, P < 0.001 (from a mean of 8.2 ± 4.5 million spermatozoa/ml of seminal plasma before treatment to a mean of 16.5 ± 5.5 million after treatment). In asth- enozoospermic patients, the increase of spermatozoa was 1.6-fold, P < 0.001 (from a mean of 29.9 ± 5.7 million spermatozoa/ml before treatment to a mean of 48.7 ± 12.8 after treatment). The same positive effects also occurred for sperm motility. Oligo-asthenozoospermic patients showed an increase of rapid progressive spermatozoa motility from a mean of 15.5% ± 4.4% before treatment to a mean of 23.1% ± 4.7% after D-aspartate treatment (1.49-fold increased, P < 0.001). The same effects occurred in oligo-asthenozoospermic patients. In these subjects the increase of rapid pro- gressive spermatozoa motility was 1.86-fold (from 11.6% ± 3.9% before treatment to 21.6 ± 7.5 after treatment, P < 0.001). In addition, the treatment of D-aspartate in these patients consequently led to a significantly increased number of pregnancies occurring in the partners of the treated patients. Conclusions:Treatment of sub-fertile patients with sodium D-aspartate improved the number and the motility of the spermatozoa and consequently improved the rate of pregnancies of their partners.
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