Sperm chromatin integrity may predict future fertility for unexplained recurrent spontaneous abortion patients.

The pathogenesis of recurrent spontaneous abortion (RSA) is multi-factorial, complex and poorly understood. In the present study, semen parameters, including sperm chromatin integrity, sperm concentration, sperm motility and sperm morphology, were compared between 111 men whose partners had a history of unexplained RSA (RSA group) and 30 healthy fertile men (control group). The RSA group was further separated into three subgroups, depending on their reproductive outcome during the 12 months after they were enrolled in the study: the pregnancy subgroup consisted of 43 men whose partners achieved a successful pregnancy up to at least the 24th week of gestation; the abortion subgroup included 31 men whose partners experienced further abortions; and the infertile subgroup had 37 men whose partners did not have any positive pregnancy test after regular, unprotected intercourse. Significantly lower proportion of sperm with normal morphology was found in the abortion subgroup (14.7 ± 4.3%) than in the control group (17.5 ± 5.0%). Sperm concentrations were significantly lower in the infertile subgroup (55.7 ± 24.1%) than in the controls (68.6 ± 27.8%). The rates of abnormal sperm chromatin integrity were significantly higher in the abortion (16.7 ± 7.7%) and infertile (16.3 ± 6.6%) subgroups, compared to the control group (13.0 ± 4.4%). Logistic regression analysis showed that the subsequent reproductive outcome of the 111 RSA patients was negatively correlated to the rates of abnormal sperm chromatin integrity. In conclusion, sperm chromatin integrity, sperm morphology, and sperm concentration were associated with future reproductive outcome of RSA patients. The sperm chromatin integrity was a significant predictor for future abortion and infertility.