Final answer:
Radiography isn't usually used in a pregnant woman because fetal exposure to ionizing radiation may harm the developing fetus.
Step-by-step explanation:
During pregnancy, radiography isn't usually used because fetal exposure to ionizing radiation may harm the developing fetus. Radiation can harm cells that reproduce rapidly, such as embryos, which is why particular care must be taken during pregnancy. Ultrasounds are the most safely used imaging study during pregnancy because they do not utilize ionizing forms of radiation.