PROBLEM: The presence of embryotoxic factors in sera from women with recurrent spontaneous abortion (RSA) has been proposed as a basis for classification of unexplained RSA. To determine the prevalence of circulating embryotoxins among women with idiopathic RSA, sera from 160 women were studied using the mouse blastocyst assay.
METHODS: Two-cell embryos were collected from superovulated mated CB6F1/J mice and cultured in media supplemented with fetal bovine serum (FBS) or 10% serum at 37°C with 5% CO2 and high humidity. Each assay was run in triplicate using three mice with at least five embryos from each mouse. Results were determined by calculating the average percentage atresia for each mouse. FBS, known to support embryo proliferation, was used to control in each assay.
RESULTS: The prevalence of embryotoxic factors among women experiencing RSA was 24.4% (39/160). There is no correlation found between the presence of embryotoxicity and phospholipid antibodies, lupus anticoagulant, and thyroglobulin/microsomal antibodies.
CONCLUSION: The embryotoxicity assay can serve as a basis for a new approach for classification of unexplained recurrent spontaneous abortion.