Radiation procedures performed on U.S. women during pregnancy: findings from two 1980 surveys.

The 1980 National Natality Survey (NNS) and 1980 National Fetal Mortality Survey (NFMS) provide a unique opportunity to examine variation in exposure to radiation during pregnancy for mothers of live-born and stillborn infants. Maternal race, age, education, and marital status in both surveys and low birth weight in the 1980 NNS are characteristics used to examine exposure rates for X-ray, ultrasound, nuclear medicine, shortwave, and microwave radiation examinations and treatments. About 15 percent of mothers of live infants and 23 percent of mothers who experienced stillbirths (fetal deaths of 28 weeks or more gestation) had a medical X-ray procedure during pregnancy. The 15 percent exposed in 1980 was a reduction from 22.5 percent of mothers exposed according to the results of the 1963 NNS; this reduction occurred in all race and age groups. About 34 percent of 1980 NNS mothers and 53 percent of 1980 NFMS mothers had ultrasound exposure during pregnancy. Radiation exposure rates were higher for 1980 NNS mothers who had low birth weight infants (under 2,500 g, or 5 lb, 8 oz) than for those who had normal weight infants.