Sperm DNA fragmentation index and pregnancy outcome after IVF or ICSI: a meta-analysis

The purpose of this study was to carry out a meta-analysis for a comprehensive understanding and estimation of the association between sperm DNA Fragmentation Index (DFI) and pregnancy outcome after in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatment. Studies concerning the link of DFI with pregnancy outcome were included after literature search of database PUBMED, EMBASE, MEDLINE. Related information was extracted from the eligible studies by two independent authors and a meta-analysis was conducted by using STATA 12.0 software. Pregnancy outcomes consisted of biochemical pregnancy (BP), clinical pregnancy (CP) and pregnancy loss (PL). The studies included for meta-analysis were divided into three groups according to the DFI threshold value (DFI > 27 %, 15-27 %, a parts per thousand currency sign15 % group). The odds ratio (OR ) and their 95 % confidence intervals (95 % CIs) were used to evaluate the association between DFI and pregnancy outcome. Twenty articles were included in our meta-analysis. The results indicated that infertile couples were more likely to get pregnant if DFI was less than threshold value (For threshold value > 27 % and 15-27 % group, combined overall OR (95 % CI) = 1.437 (1.186-1.742), 1.639 (1.093-2.459) respectively). However, when stratified by DFI detection methods, using sperm chromatin structure assay (SCSA) as the DFI test method, the results indicated a similar CP rate between groups with a high DFI or a lower DFI value (SCSA, For threshold value > 27 % and 15-27 % group, combined overall OR (95 % CI) = 1.242(0.978-1.577), 1.480(0.921-2.377) respectively). The meta-analysis based on BP (overall OR (95 % CI) = 0.952 (0.697-1.302)) and PL((For DFI > 27 %, 15-27 %, a parts per thousand currency sign15 % group, OR (95 % CI) = 0.786 (0.491-1.258), 1.509 (0.655-3.476), (0.538 (0.264-1.097) respectively) outcome yielded nonsignificant results. The predication value of DFI for IVF or ICSI outcome is not confirmed in our meta-analysis. Further better designed studies with larger subjects involved are needed to better address this issue.