This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pregnancy in Rh-negative Women, Subject name: Gynaecology & Obstetrics
Causes of Hydrops fetalis: 
Select and explain. 
A. Parvovirus, B. Herpes, C. CMV, D. HIV
A: Parvovirus
Answer: A: Parvovirus 
Explanation: Ans. (A) Parvovirus(Ref: William's Obstetrics 25th Ed; Page No 309)Parvovirus B19 is the most common infectious cause of hydrops fetalis.Parvovirus B19 infects fetal erythroid progenitor cells and cause anemia.Severe anemia leads to high-output cardiac failure and hydrops fetalis.