Sperm DNA fragmentation in Italian couples with recurrent pregnancy loss

Abstract

The aetiopathogenesis of recurrent pregnancy loss (RPL) is heterogeneous. The aim of this study was to investigate the male factor in Italian couples experiencing RPL following natural conception. The study investigated 112 men from RPL couples and two control groups: 114 infertile men with one or more impaired semen parameters and 114 fertile men with high-quality semen parameters. Semen parameters were examined according to WHO criteria. Sperm DNA fragmentation (SDF) was evaluated using TdT-mediated dUDP nick-end labelling (TUNEL) assay. With the exception of ejaculate volume, the seminal profile of patients with RPL was similar to that of fertile patients and better than the infertile ones. Despite good spermatogenesis, however, sperm DNA integrity was impaired in the RPL group, with SDF values significantly higher than in fertile controls (18.8 ± 7.0 versus 12.8 ± 5.3, P < 0.001) and similar to those of infertile patients. SDF also showed a positive correlation with the age of patients with RPL and number of miscarriages. The results suggest a correlation between increased SDF and impaired reproductive capacity in terms of both fertilization and pregnancies carried to term, but high SDF cannot yet be considered a predictive factor for the risk of RPL.

Keywords: male infertility; miscarriage; semen quality; sperm DNA integrity; spermatozoa.