Which congenital infection is classically associated with fetal hydrops and severe neonatal anemia?

• A. CMV
• B. Toxoplasma
• C. Parvovirus B19 with fetal hydrops and severe neonatal anemia
• D. Rubella

Answer: (C)

Parvovirus B19 is classically linked to fetal hydrops and severe neonatal anemia because it directly targets erythroid precursor cells, causing erythroid aplasia in the fetus. This drastic reduction in red blood cell production leads to severe fetal anemia, which drives high-output cardiac failure and nonimmune hydrops fetalis (edema, fluid in body cavities, organomegaly). After birth, the persistent suppression of erythropoiesis can result in ongoing severe anemia, often requiring transfusion. Other congenital infections produce different findings—CMV with microcephaly and periventricular calcifications, Toxoplasma with hydrocephalus and chorioretinitis, Rubella with cataracts, PDA, and deafness—whereas Parvovirus B19’s hallmark in this context is the combination of fetal anemia and hydrops.