Intrauterine interventions for severe fetal anemia due to parvovirus B19 national outbreak

Parvovirus B19 infection during pregnancy can cause severe fetal anemia, hydrops fetalis, and fetal death. This study describes our experience managing ten cases of severe fetal anemia due to parvovirus B19 infection during the 2023-2024 national outbreak in Israel.

This single-center descriptive cohort study included ten singleton pregnancies with fetal anemia (MCA-PSV >1.5 MoM) requiring intrauterine transfusion. Parvovirus B19 infection was confirmed by maternal IgM serology and/or amniotic fluid PCR. For pregnancies <20 weeks of gestation, we implemented a modified intraperitoneal transfusion technique incorporating pre-transfusion ascites drainage. Intravascular transfusions were used for later gestations. Platelet transfusions were administered when thrombocytopenia was present. Serial fetal sonography and neuroimaging were performed throughout the follow-up period.

Seventy percent of fetuses presented with anemia and hydrops before 20 weeks of gestation. The modified intraperitoneal transfusion technique doubled the mean transfused packed red blood cell volumes compared to the standard technique (40 mL vs. 20 mL; p = 0.009). We performed 15 intraperitoneal transfusions (mean 2.14 per fetus) and 11 intravascular transfusion procedures. One fetal death occurred following intraperitoneal transfusion. Complications included one iatrogenic abdominal wall defect post-intraperitoneal transfusion (successfully repaired postnatally) and one case of transient ascites with hemosiderin deposits (resolved after birth). Two fetuses required platelet transfusions. All surviving infants demonstrated normal neuroimaging. Mean gestational age at delivery was 37 weeks 5 days, with 88% delivered at term. One preterm delivery occurred at 27 weeks due to cervical shortening and contractions, resulting in neonatal complications of prematurity.

Intensive intrauterine intervention, including ascites drainage and repeated red blood cell and platelet transfusions, may improve fetal outcomes in severe parvovirus B19 anemia. The modified intraperitoneal transfusion technique with pre-transfusion ascites drainage enabled larger transfusion volumes. Early, aggressive intervention appears crucial for optimal outcomes in these challenging cases.