Pregnancy-associated thrombotic microangiopathy (TMA) is a rare condition, but it is burdened by a significant perinatal and maternal morbidity as well as mortality. We describe the case of a 33-year-old woman, who developed a TMA at the 36th week of gestation characterized by increased LDH, haptoglobin consumption, schistocytes, thrombocytopenia and acute renal failure requiring dialysis. There were not gestational hypertension nor proteinuria until the day of hospitalization. ADAMTS 13 deficiency was ruled out and the patient did not have diarrhea. She was initially treated with caesarean section, plasma infusion and plasmapheresis with no benefit. Five days after the onset of TMA, a temptative diagnosis of atypical uremic syndrome (aHUS) was made and the patient was switched to eculizumab. Antibiotic prophylaxis and anti-meningococcal A,B, C, W135 and Y vaccination was performed. TMA rapidly resolved and renal function completely recovered. The newborn had a normal perinatal course. A complement dysregulation was ruled out by testing for mutations on CFH, CFHR3-R1, CFI, MCP, CFB, C3 and for anti CFH antibodies. In conclusion the differential diagnosis of aHUS with HELLP syndrome is often not straightforward. The severity and persistence of TMA, the high mortality associated to peripartum TMA and the risk for irreversible kidney failure require an early therapeutic decision as to the use of eculizumab.