Sternberg J
Can Med Assoc J. 1973 Jul 7;109(1):51-7.
Irradiation during pregnancy may occur either as the result of radioactive pollution of the environment, or during a medical procedure using x-rays or radionuclides. While the former is usually unforeseeable, the latter is known and accepted by both physician and patient.Recent statistics estimate that about one quarter of pregnant women have had a radiographic experience during the pregnancy, either for obstetrical reasons or in the course of medical and dental examinations. The amount of radiation delivered to the fetus is in the range of one rad or less. Radionuclidic procedures may result in fetal radiocontamination, chiefly after placental transfer and fetal uptake. Radioiodine, radioactive calcium and selenomethionine are dangerous for the fetus, since they cross the placenta freely and are taken up by fetal tissues. The labelled proteins, radiocolloids and some mercury compounds remain in the maternal compartment and therefore can affect the fetus only through their gamma radiation at some distance from the fetus.The teratogenic effect, the leukemogenic threshold and the lowered resistance to neonatal infections have been demonstrated after irradiation with doses far higher than those encountered during diagnostic applications of ionizing radiation. Statistical data suggest an increase of susceptibility to leukemia in infancy after intra-uterine irradiation at a diagnostic level. Cytogenic analysis may.... offer valuable data for the establishment of the extent of radiation damage.
孕期受辐射可能是环境放射性污染所致，也可能是在使用X射线或放射性核素的医疗程序中发生。前者通常不可预见，而后者医生和患者都清楚并认可。最近的统计数据估计，约四分之一的孕妇在孕期有过放射检查经历，要么是出于产科原因，要么是在医疗和牙科检查过程中。胎儿所接受的辐射量在1拉德或更低范围内。放射性核素程序可能导致胎儿放射性污染，主要是在胎盘转移和胎儿摄取之后。放射性碘、放射性钙和硒代蛋氨酸对胎儿危险，因为它们能自由穿过胎盘并被胎儿组织摄取。标记蛋白质、放射性胶体和一些汞化合物留在母体部分，因此只能通过在距胎儿一定距离处的γ辐射影响胎儿。在用远高于电离辐射诊断应用中所遇剂量进行照射后，已证实有致畸作用、致白血病阈值以及对新生儿感染抵抗力降低。统计数据表明，在诊断水平的宫内照射后，婴儿期患白血病的易感性增加。细胞遗传学分析可能……为确定辐射损伤程度提供有价值的数据。
