The effects of in utero diagnostic X-irradiation on the development of preschool-age children.

High doses of X-irradiation may affect the developing human embryo and fetus, causing brain, eye, skeletal and other defects. Although the doses used in diagnostic irradiation are not considered to be high enough to cause fetal anomalies, it is unknown whether they affect the long-term development of the in utero exposed children. Using the Bayley or McCarthy developmental scales we examined 52 children born to mothers exposed to diagnostic X-irradiation of the abdomen and/or pelvis during the first trimester of pregnancy, 60 children born to mothers exposed during pregnancy (58 in the first trimester) to X-rays in areas other than the abdomen or pelvis, and 62 normal children without maternal exposure to X-rays during pregnancy. All children were aged 1-5 years at examination. Parental socioeconomic status was the same in all three groups. There were no differences in the results of the medical and neurological examination, and in the motor or congnitive scores among three groups. Embryonic or fetal exposure to X-irradiation in doses below 5 rads does not seem to have any effect on development during childhood.