Regular Article CLINICAL TRIALS AND OBSERVATIONS Pregnancy outcomes following recovery from acquired thrombotic thrombocytopenic purpura

Pregnancy is a recognized risk for precipitating acute episodes of thrombotic thrombocytopenic purpura (TTP), creating concern for the risk of recurrent TTP associated with pregnancies following recovery. Among women with hereditary ADAMTS13 deficiency, the occurrence of an acute episode of TTP during pregnancy with fetal loss is commonly reported and may be inevitable without plasma prophylaxis. The risk of pregnancy following recovery from TTP associated with the more common acquired, severe ADAMTS13 deficiency has also been an important concern. Patients with TTP associated with acquired, severe ADAMTS13 deficiency are at risk for relapse and most of these patients are women in their childbearing years. We previously reported that the frequency of recurrent TTP with a subsequent pregnancy among all women in the Oklahoma TTPHUS Registry was low compared with the high frequency in published case reports. The 19 women in our previous report had their initial episode of TTP–hemolytic uremic syndrome (TTP-HUS) in 1990 to 2001; only 6 women had ADAMTS13 measurements and only 3 had ADAMTS13 activity,10%. In some of the 16 women without documented ADAMTS13 deficiency, the etiology of the initial episode was subsequently attributed to disorders other than TTP, such as preeclampsia, Hemolysis, Elevated Liver function tests, and Low Platelets (HELLP) syndrome, antiphospholipid syndrome, Shiga toxin, and cocaine toxicity. Similarly, the systematic literature search in our previous report identified all reports of patients with a diagnosis of TTP, HUS, or thrombotic microangiopathy and a subsequent pregnancy, between 1968 and 2002, without consideration of ADAMTS13 activity. For this report, we selected womenwho had had TTP associated with acquired, severe ADAMTS13 deficiency (ADAMTS13 activity ,10%) for 3 reasons: (1) ADAMTS13 activity ,10% supports the diagnosis of TTP; (2) following recovery, these women have an increased prevalence of hypertension and systemic lupus erythematosus (SLE) which are risk factors for complications of pregnancy; and (3) recurrent TTP rarely occurs in patients with ADAMTS13 activity $10%.We focused not only on the risk for recurrent TTP but also on the occurrence of preeclampsia and other pregnancy complications as well as the children’s outcomes. To compare our experience to the experience in published reports, we performed a systematic literature review to identify all case reports of pregnancies in women following recovery from TTP associated with acquired, severe ADAMTS13 deficiency.