The atypical HUS (aHUS) is a rare genetic disease, with poor prognosis, characterized by microangiopathic hemolytic anemia, thrombocytopenia and acute renal failure. This syndrome is often related to mutations in the genes encoding complement regulatory proteins. A 26-year-old woman with homozygous mutation in complement factor H (CFH) developed a relapse of aHUS at 17th week of pregnancy. Despite treatment with plasma exchange (PEX), at the 26th week of gestation eculizumab was started. The sequential treatment with eculizumab after PEX was well tolerated and it has led to clinical remission.