Conception plans miscarry with sperm DNA damage

By Sally Robertson, B.Sc.Jul 30 2012

Sperm with damaged DNA are more likely to cause spontaneous pregnancy loss, report researchers.

However, it should be possible to reduce such losses during assisted conception if sperm are screened for DNA damage before injection, they say.

In a meta-analysis of data from 16 studies, a significant relationship was found between having a high frequency of sperm with elevated DNA damage and miscarriage among 2969 couples who conceived either spontaneously or via assisted conception.

A previous meta-analysis of seven studies reported an association between sperm with DNA damage and pregnancy loss after in vitro fertilization and intracytoplasmic sperm injection, say Lynne Robinson (Birmingham Women's Hospital, UK) and colleagues.

The current study reviews an additional nine studies and addresses the matter of DNA fragmentation in both spontaneous and assisted conception.

As reported in Human Reproduction, the researchers found a significant increase in miscarriage in patients with high DNA damage compared with those with low DNA damage, at a relative risk of 2.16.

Analysis of the different types of assays used to assess DNA damage showed that the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was the most reliable method for detecting damage that may cause a miscarriage.

"This method of analysis directly quantifies DNA damage by the incorporation of labeled dUTP [diphosphatase] into single- and double-stranded DNA breaks," explains the team.

The association between sperm DNA damage and miscarriage was also significant for the sperm chromatin structure assay but not for the COMET (also known as the Single Cell Gel Electrophoresis assay) or the acridine orange test.

"Tests for DNA damage and selection of undamaged sperm should be considered as part of the diagnostic and treatment pathways for those suffering from recurrent pregnancy loss," conclude Robinson and team.

In addition, further research is needed to investigate the mechanisms responsible for and preventing the DNA damage, they say.

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