Radiobiology

In Utero Exposure Scenario

Question: A woman receives 35 rads (0.35 Gy) to the abdomen. She conceived 8 days ago. From the exposure, her fetus is at greatest risk of:

A. Prenatal death

B. Mental retardation

C. Major structural abnormality

D. Leukemia

	Answer: A. (Prenatal death) If the conceptus survives, it will not be at increased risk for other malformations. While the first 12 days post-conception tend to be "death or nothing", the risk of death from radiation exposure is actually highest during weeks 3 through 5, the period of organogenesis.