Idiopathic recurrent pregnancy loss: role of paternal factors; a pilot study

This case-control study was designed with the aim of evaluating the role of sperm, oxidative stress and DNA damage in idiopathic recurrent pregnancy loss (iRPL). This pilot study is the first study done on the Indian population which reports the association between DFI, TAC and ROS in couples experiencing iRSA.

Twenty infertile men with a history of iRPL and 20 fertile controls (having fathered a child a year earlier) were included in the study which was performed in Laboratory for Molecular Reproduction and Genetics, India, from March 2010 to July 2011. The female partners of the participants were normal on gynaecological examination and had normal endocrine and blood profiles. Conventional semen analysis was performed (concentration, motility, morphology; WHO criteria, 2010) within 1 hour of sample collection. Levels of reactive oxygen species (ROS) were assessed by luminol-dependant chemiluminescence. The total antioxidant capacity (TAC) was quantified by ELISA. The Sperm chromatin structure assay (SCSA) was performed by flow cytometry to determine DNA fragmentation Index (DFI). Statistical analysis was performed using SPSS version 15 and parameters were compared by Mann-Whitney test. Pearson correlation test was used to find the correlation between parameters and a p-value <0.05 was considered significant. Receiver operating characteristics (ROC) curve analysis was applied to find out the cut-off value of DNA fragmentation index.

No significant differences in age, seminal volume, liquefaction time, pH and sperm concentration were observed between the male partner of iRPL cases and the controls, but sperm morphology and motility were significantly (p <0.05) lower in the male partner of cases with idiopathic recurrent spontaneous abortion (RSA). The mean ROS levels observed were 47427.00 relative light unit (RLU)/min/20 million sperm in the male partners as compared to 13644.57 RLU/ min/20 million sperm in the controls (normal <15000 RLU/min/20 million). The mean TAC levels in the controls (6.95 mM trolox) were significantly (p <0.05) higher as compared to the male partners of women with IRPL (2.98 mM trolox). The average mean DFI of male partners were found to be 23.37±9.9 and the mean DFI of controls was 13.89±5.40. The mean DFI was significantly (p <0.05) higher when compared to the controls. The range of DFI in male partners was 8.50-44.07. However, in the controls the range was 7.70-23.50.

Sperm DNA integrity is critical for normal embryonic development and birth of healthy offspring. Oxidative stress due to the imbalance between raised free radical levels and low total antioxidant capacity is one of the critical causes of DNA damage. Thus assay of oxidative stress and sperm genomic integrity is essential in couples with iRSA following natural and spontaneous conception.