Pregnancy-associated atypical hemolytic uremic syndrome without recurrence: A 10-year follow-up including a subsequent pregnancy

Atypical hemolytic uremic syndrome (aHUS) is a rare, life-threatening thrombotic microangiopathy caused by dysregulated complement activation. Pregnancy-associated aHUS (p-aHUS), which frequently develops postpartum, can lead to acute kidney injury. However, long-term outcomes, including subsequent pregnancies, remain poorly described. We report a 24-year-old primiparous woman who developed p-aHUS three days after cesarean delivery at 41 weeks' gestation. She presented with thrombocytopenia, hemolytic anemia, and acute kidney injury. Plasma exchange was initiated, resulting in hematologic and renal recovery by postpartum day 12. Genetic testing revealed a heterozygous missense variant in the C3 gene, classified as a variant of uncertain significance. Despite not receiving complement inhibition therapy, her renal function remained stable. She experienced no recurrence during a subsequent pregnancy three years later and had normal renal function at 10-year follow-up. This case suggests that long-term renal preservation is achievable, with successful subsequent pregnancy, in selected p-aHUS patients even without complement inhibition.