Supplementary Material for: Intrauterine Blood Transfusion for Parvo B19 Induced Fetal Anemia: Neuroimaging Findings and Long-Term Neurological Outcomes

INTRODUCTION: We aimed to evaluate neuroimaging findings and long-term neurodevelopment of fetuses and children following intrauterine blood transfusion [IUT] for parvo B19 infection induced anemia compared to those with RBC alloimmunization. METHODS: We conducted a retrospective cohort study including women who underwent an IUT due to fetal anemia between 2006 to 2019 in a tertiary, university-affiliated medical center. The cohort was divided into two: a study group - fetuses affected by congenital parvo-B19 infection; and a control group - fetuses affected by RBC alloimmunization. Retrospective data such as antenatal sonographic evaluations, fetal brain MRI results and short-term fetal and neonatal outcomes were collected. All children underwent a neurodevelopmental evaluation after birth using a Vineland questionnaire. Primary outcome was defined as the presence or absence of neurodevelopmental delay. Secondary outcome was defined as the presence of abnormal fetal neuroimaging findings such as cerebellar hypoplasia, polymicrogyria, intracranial hemorrhage or severe ventriculomegaly. RESULTS: Overall, 71 fetuses requiring at least one IUT were included in the study. Of these, 18 were affected by parvo B19 infection and 53 by RBC alloimmunization with various associated antibodies. Fetuses in the parvo B19 group presented at an earlier gestational age [22.91 ± 3.36 weeks vs. 27.37 ± 4.67 weeks, p=0.002] and were more affected by hydrops [93.33% vs. 16.98%, p<0.001]. Three fetuses out of the 18[16.67%] fetuses in the parvo B19 group died in utero following the IUT. Abnormal neuro-imaging findings were detected in 4/15 [26.7%] of the parvo B19 survivors vs. 2/ 53 [3.8%] of fetuses affected by RBC alloimmunization [p=0.005]. There was no difference in long-term neurodevelopmental delay rates between the children in the study and control groups, as assessed at the average age of 3.65 and 6.53 years, accordingly. CONCLUSION: Fetal anemia due to parvo B19, treated with IUT, might be associated with increased rates of abnormal neuro-sonographic findings. The correlation between those findings and long-term adverse neuro-developmental outcomes requires further investigation