Introduction. One of the possible causes of idiopathic infertility (II) is the DNA fragmentation (DNAF), break of the single or both chains of the DNA molecule. Reducing the severity of fragmentation is reasonable as treatment modality. Hyperbaric oxygenation (HBO) was studied with regard to the changes in DNA fragmentation severity. 

Materials and methods. Ninety men with II and increased DNAF were included. Sixty patients received 10 procedures of HBO each, 3 months thereafter in-vitro fertilization (IVF) was attempted. IVF without HBO was carried out in control group of 30 patients. Median age was 30.5 years (range 25-37). DNAF severity was assessed at the entry in the study and 3 months after finishing the course of HBO in the study group and at the entry and 3 months thereafter in control group. TUNEL was used to assess DNAF, 15% was selected as the upper limit of the normal area. 

Results. Significant decrease in DNAF was evident in study group from 33.2±7.5% to 11.9±5.9% (p< 0,05). In the control group no significant changes were detected with DNAF severity at the level of 31.7%±6.3%. Pregnancy rate was 63.3% (38/60) in the study group and 36.7% (11/30) in the control group (p< 0.05). 

Conclusions. Correction of the spermatozoid DNAF is important for male fertility. High efficacy of HBO allows to account for it as the perspective method of treatment in male patients with idiopathic infertility.