The most dangerous time for a fetus to be exposed to X-ray radiation is during the

• A. First trimester
• B. Second trimester
• C. Third trimester
• D. After birth

Answer: (A)

During the early weeks of pregnancy, the fetus is most radiosensitive because organs are forming and cells are dividing rapidly. Ionizing radiation can disrupt development at this stage, potentially causing congenital anomalies or fetal loss. As pregnancy progresses into the second and especially the third trimester, most organs are already formed and cell division rates slow, so the same dose of radiation poses a smaller risk. After birth there is no fetus to be affected. Therefore, the time with the greatest risk from fetal X-ray exposure is the first trimester.