None of the 15 women received regular prophylactic plasma infusion or exchange during gestation, as part of a planned pregnancy; prophylactic plasma-exchange was performed after detection of severely deficient ADAMTS13 activity levels (i.e., <10%) in patients 1 and 2 but, nevertheless, they developed gravidic TTP. Here, ADAMTS13 is linked to thrombotic thrombocytopenic purpura.