Despite the low prevalence of thrombotic thrombocytopenic purpura, the finding in a pregnant woman of the triad consisting of anemia, thrombocytopenia, and neurological changes should guide clinical diagnosis, and should prompt measurement of the metalloprotease ADAMTS-13 in order to rule out or confirm diagnosis of thrombotic thrombocytopenic purpura and evaluate the best therapeutic option. This evidence concerns the gene ADAMTS13 and anemia (phenotype).