This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Diagnosis of Pregnancy, Subject name: Gynaecology & Obstetrics
Blighted ovum is characterized by: 
Select and explain. 
A. Avascular villi, B. Syncytial knot, C. Intervillous haemorrhage, D. Intracerebral haemorrhage
A: Avascular villi
Answer: A: Avascular villi 
Explanation: A blighted ovum is a feilized egg that implants but does not develop. In a blighted ovum, a gestational sac forms and grows; however, the embryo does not develop. So blighted ovum is also known as Anembryonic pregnancy. Blighted Ovum - Criteria Mean sac diameter >=25 mm No yolk sac/ Embryo seen Avascular Villi Non Viable Pregnancy