Background Anemia is an important complication in fetuses. In Southeast Asia, Hb Bart’s disease is the main cause of fetal anemia, although other causes are increasingly identified.
Objective To characterize the etiologies and outcomes of fetal anemia at a tertiary-care hospital in
Northern Thailand.
Methods A retrospective chart review of pregnant women who were followed at Chiang Mai University
Hospital with a fetal diagnosis of anemia or hydrops fetalis or Hb Bart’s disease from 2014 to 2021 was
conducted.
Results One-hundred and twenty-three cases from 116 pregnancies were identified. The median (IQR)
gestational age (GA) was 20 (10) weeks. Forty-five cases (36.6%), 42 identified by prenatal screening,
had Hb Bart’s disease. Twenty-seven cases (21.9%) had fetal anemia and/or hydrops fetalis; 7 twins with twin-to-twin transfusion syndrome (TTTS), 3 hereditary pyropoikilocytosis, 1 suspected red cell
membrane disorder, 3 homozygous Hb Constant Spring (CS), 1 Rh-alloimmune hemolytic anemia, 1 Hb H/Pakse, 1 transient abnormal myelopoiesis, 1 chromosome abnormality and 2 unknown cause. Fifty-one cases (41.5%) had hydrops fetalis not associated with anemia. The mean GA of non Hb Bart’s anemia and TTTS were 25 (8) and 27 (8.75) weeks, respectively Intrauterine transfusion was given in selected cases of fetal anemia which rendered good outcome.
Conclusions Fetuses with hemolytic anemias usually present in the second or third trimester. Hb Bart’s disease remains the major cause of fetal anemia. Other emerging causes include homozygous Hb CS and red cell membrane disorders.
