Pregnancy carries a high risk for various forms of thrombotic microangiopathy(TMA), including thrombotic thrombocytopenic purpura and P-aHUS. Preeclampsia (PE) and HELLP might be a trigger of P-aHUS. To describe the subpopulation of P-aHUS patients, to search clinical and anamnestic prognostic markers of the course of the disease. The throughout analysis of 36 cases of p-aHUS. The median age of patients was 30 years (25–33). All patients received plasma therapy (30–40 ml/kg), in 13 cases Eculizumab was administered. The patients were divided into two groups: Gr.1 have consisted of patients surviving the episode of TMA (n = 25, Md 30 years (25–34)), gr.2- those who did not (n = 11, Md 35 years (32–44)). Groups were compared using following criteria: age, amount of pregnancies and deliveries in anamnesis, gestational complications in previous pregnancies, volume of surgical treatment, treatment with antibiotics, antithrombotic therapy, organ lesions, laboratory markers. Gr.2 had a greater number of previous pregnancies and births (3 pregnancies (2.25, 4), P = 0.03, 2 (2, 3) births, P = 0.03), a greater frequency of surgical interventions (including caesarian section) in a larger volume than the cesarean section (30.6% gr1, 63.6% gr2, P = 0.01) and greater frequency of previous PE/HELLP. Gr2 had a higher rate of developing acute heart failure (27.3% vs 4%, p = 0,1), respiratory distress syndrome (90.9% vs 60,0%, p = 0.01), acute cerebrovascular events ( in total and ischemic stroke, 27.3% vs 0%, p = 0.01). The superimposed sepsis was more frequently observed in the gr.2 (45.5% vs 0%, D = 0.01). The revealed regularities allow us to assume the presence of the following triggers for the development of p-aHUS: surgical interventions and gestational complications. Apparently, TMA in the group of the dead was heavier and more pronounced, it was more often complicated by the septic process. Further development of protocols for antibiotic therapy is necessary.