Background Atypical hemolytic uremic syndrome is a rare disorder which is known to cause acute thrombotic microangiopathy during pregnancy with poor maternal and fetal outcomes. Atypical hemolytic uremic syndrome is caused mostly by dysregulation of alternative complement pathway secondary to genetic mutations. Most of the cases reported have been in the post-partum period. We report a rare case of a patient who presents with thrombotic microangiopathy in the first trimester of her eleventh pregnancy and was successfully treated with eculizumab.