This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Obs), Subject name: Gynaecology & Obstetrics
The surest sign of intrauterine death includes 
Select and explain. 
A. Small sized fetus, B. Over riding of cranial bones, C. Spalding's sign, D. Gas in aorta
D: Gas in aorta
Answer: D: Gas in aorta 
Explanation: (D) Gas in aorta # Straight X-ray abdomen: The following features may be found in varying degree, either singly or in combination.> Hyperflexion of the spine is more common. In some cases hyperextension of the neck is seen.> Crowding of the ribs shadow with loss of normal parallelism.> Appearance of gas shadow (Robert's sign) in the chambers of the heart and great vessels may appear as early as 12 hour;; but difficult to interpret. When detected, provides conclusive evidence.