Ohmura K, et al. - Researchers investigated whether anti-C1q antibodies (anti-C1q) are related to the activation of complement pathway in recurrent pregnancy loss (RPL). In unexplained RPL vs in healthy parous individuals, a significantly higher prevalence, as well as titre of anti-C1q, was demonstrated. The occurrence of complement activation as well as a frequent finding of a high ratio of pregnancy loss and fetal growth restriction were reported in mice treated with JL-1 (a monoclonal anti-mouse C1q antibody). In these mice, these pathogenic changes were cancelled by C5a receptor (C5aR) blockade. Overall, a link between the prevalence of anti-C1q and RPL was found in this study. Using murine model, it was shown that reproductive failure could be induced by anti-C1q, and therapy targeting the C5-C5aR axis might ameliorate it.