Abnormalities in children exposed to x-radiation during various stages of gestation: tentative timetable of radiation injury to the human fetus. I.

Abstract

Severe and obvious abnormalities encountered in 26 children who received heavy x-radiation during various stages of gestation were compiled and evaluated. The following conditions occurred most frequently: stunted growth, microcephaly, mental retardation, microphthalmus, pigmentary degeneration of the retina, cataracts, genital and skeletal anomalies. A tentative timetable for man is presented which correlates specific types of abnormalities with irradiation during particular stages of gestation when the dose is in the range of therapeutic irradiation. On the basis of the patient material presently available and with some support of experimental data the following generalizations are made: (1) Moderately large dose of ionizing radiation (over 250 R but the upper limit cannot be stated) delivered to the human embryo before 2–3 weeks of gestation is not very likely to produce severe abnormality in most of the children born although experimental data indicate that considerable numbers of these embryos are resorbed or aborted (23,24). (2) Irradiation of the fetus with doses used in medical therapeutics between 4 and 11 weeks of gestation would lead to severe abnormalities (predominantly malformation) of many organs in most or all of the children. (3) Irradiation in a similar dose range between 11 and 16 weeks of gestation may produce little or no eye (late cataracts not considered), skeletal and genital organ abnormalities but stunted growth, microcephaly and mental retardation is frequently present. (4) Irradiation of the fetus between 16 and 20 weeks of gestation with a similar dose range may lead only to mild degrees of microcephaly, mental retardation and stunting of growth. (5) Irradiation of the fetus with a similar dose range after 20 weeks of gestation is not likely to produce overt abnormalities leading to a serious handicap in early life. However, a proportion of the infants may show evidence of irradiation exposure such as skin erythema, abnormal pigmentation, epilation, or deficiencies in the hematopoietic system.