This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
Diagnostic radiation in a pregnant woman may cause: 
Select and explain. 
A. High fetal exposure, B. Low birth weight babies, C. Abortion, D. Genetic abnormalities in the fetus
B: Low birth weight babies
Answer: B: Low birth weight babies 
Explanation: Fetal exposure during dental X-rays is only about 1 microgray, which is lesser than background radiation. However, maternal radiation dose to thyroid gland from dental radiographs can cause low birth weight infants.