Pregnancy is an initiating event for acute thrombotic thrombocytopaenic purpura (TTP). There is a high risk of relapse during pregnancy and of foetal morbidity. We describe five cases with successful maternal and foetal outcomes in patients with a history of TTP. Cases 1 and 2 presented with TTP in their first pregnancy and had second-trimester foetal losses. Case 3 had four TTP relapses and soon after achievement of clinical remission became pregnant. Case 4 presented with TTP and left-sided stroke in pregnancy. ADAMTS-13 activity was less than 5% at presentation in four patients and prior to therapy during pregnancy in cases 1-4. Case 5, who had a single acute episode of TTP and became pregnant 6 years later, had normal ADAMTS-13 activity throughout pregnancy. Only case 3 had evidence of an inhibitor on mixing studies. All five patients underwent close haematological and obstetric monitoring and continued low-dose aspirin throughout pregnancy. Patients 1-4 had regular plasma exchange and received low molecular weight heparin during pregnancy. Patient 4 also received rituximab during the third trimester with no observed maternal or neonatal toxicity. Live healthy infants were delivered in all five cases in the third trimester. These findings suggest that successful pregnancy outcome is achievable in patients with a history of TTP and that patients with severely reduced ADAMTS-13 activity at the onset of pregnancy, necessitates regular plasma exchange during pregnancy.

Pregnancy is an initiating event for acute thrombotic thrombocytopenic purpura (TTP). Patients with a history of TTP have a high risk of relapse during pregnancy with associated maternal and fetal morbidity/mortality. We report 5 TTP patients who underwent serial clinical and laboratory monitoring (haemoglobin, platelets, blood film, reticulocytes, lactate dehydrogenase (LDH), ADAMTS-13 activity and IgG antibodies) and treatment within a specialist obstetric/haematology clinic, resulting in successful pregnancy outcomes. Patients: Cases 1 and 2 presented with TTP in their first pregnancy and had second trimester fetal losses. Case 3 had four TTP relapses and soon after achievement of clinical remission became pregnant. Case 4 had a single acute episode of TTP 6 years prior to pregnancy and normal ADAMTS 13 activity at the onset of pregnancy. Case 5 presented with acute TTP and a left sided stroke at 16 weeks gestation. ADAMTS-13 activity was <5% at onset of pregnancy in cases 1–3 and at presentation of TTP during pregnancy in case 5. Only case 3 had IgG antibodies to ADAMTS13. Cases 1–3 received regular plasma exchange (PEX) every 2 weeks initially, starting during the first trimester, with ADAMTS 13 activity levels maintained >15% during pregnancy (range 15–78%, normal range 66–126%) by collagen binding assay. Case 4 had normal laboratory parameters, including serial ADAMTS 13 activity levels, throughout pregnancy, requiring no specific therapy for TTP. Case 5 received intensive PEX (84 procedures) and pulsed methylprednisolone during pregnancy. Rituximab (375mg/m2, weekly for 4 weeks) was given at 28 weeks gestation with no observed toxicity except asymptomatic transient neonatal neutropenia. All 5 cases continued low dose aspirin (75 mg daily) throughout pregnancy. Case 1 and 2 received prophylactic low molecular weight heparin (LMWH) and cases 3 and 5 received treatment doses of LMWH for pulmunory emboli and TTP associated stroke at presentation. Live healthy infants were delivered in all 5 cases in the third trimester (31–41 weeks). These data suggest successful pregnancy outcome is achievable in patients with a history of TTP/acute TTP with therapy based on close clinical and laboratory monitoring. Regular PEX in patients with a history of TTP and severely reduced ADAMTS 13 activity/IgG antibodies to ADAMTS 13 at the onset of pregnancy was associated with successful pregnancy outcome. Serial ADAMTS 13 activity and antibody levels during pregnancy and post-partum provided a useful adjunct to decision making on intensity of treatment.