Brief Communication: Effects of Diagnostic Irradiation During Pregnancy on Head Circumference at Birth

Abstract

A historical cohort study was carried out to evaluate the effects in utero medical ionizing radiation on head circumference at birth. The nature of medical practice in Rochester, Minnesota, and the Mayo Clinic medical records linkage system enabled us to provide accurate estimates of medical radiation absorbed dose in 9,793 pregnancies of 2,980 women pregnant in Rochester between 1917 through 1973. Data were controlled for sex of the fetus, duration of pregnancy and congenital head abnormalities. It was found that medical ionizing radiation in the second and third trimesters of more than 300 mrad were related to significantly decreased head circumference. There was no significant effect of radiation exposure in the first trimester or periconceptional period. Medical ionizing radiation in the second and third trimesters of more than 300 mrad is related to a significant yet minimal, decreasing head circumference at birth. Maximum effects were seen during the midgestational and second trimester periods.

Radiation exposure in pregnancy: outcomes, perceptions and teratological counseling in Turkish women

“…The rate of anomalies in the group exposed to more than 5 mGy radiation is slightly higher than expected. Although these abnormalities are not related to radiation effects and this result is not statistically significant, previous literature indicate that some eye anomalies 29 and reduced head circumference 30 occurred following low-dose radiation exposure.…”