A new study has found that the development or reactivation of autoimmune hemolytic anemia (AIHA), of which cold agglutinin disease (CAD) is a form, during pregnancy is rare but potentially serious. The study, published in Blood, noted that severe complications (maternal and fetal) occurred in up to 25% of cases with active hemolysis.

“AIHA management during pregnancy and lactation is not standardized and drug use is often limited by safety concerns,” the authors wrote. “Here, we report the results of a multicenter retrospective cohort study evaluating AIHA impact on pregnancy focusing on disease severity, treatment need, and maternal and fetal outcome.”

The research team conducted a multicenter, retrospective cohort study on 31 women with either warm, cold, mixed, or atypical AIHA at 11 centers in Europe between 1997 and 2022. A control group of 56 healthy age- and pregnancy decade-matched women served as controls.

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The breakdown of AIHA diagnoses among the cohort was 21 warm, 2 CAD, 3 mixed, and 5 atypical forms. Diagnosis occurred prior to pregnancy in 16 women, all of whom were treated with at least 1 therapy. Nine women developed AIHA during their pregnancy, and 2 developed it postpartum.

Ten maternal complications and 10 fetal adverse events were reported. AIHA was associated with a significantly increased risk of fetal adverse events compared to that of the control group, and the adverse events were more severe in the AIHA group. There were 2 perinatal deaths secondary to placental detachment and COVID-19 infection in women on active AIHA treatment.

Treatment for AIHA during pregnancy required red blood cell transfusions in 50% of the cases and steroid treatment in all women. The research team recommends close monitoring of patients at risk of AIHA during or after pregnancy.


Bortolotti M, Fantini N, Glenthøj A, et al. Autoimmune hemolytic anemia during pregnancy or post-partum: an international multi-center experience. Blood. 2022;140(Suppl 1):2440-2442. doi:10.1182/blood-2022-156656