Expert reviewObstetricsFear of the unknown: ionizing radiation exposure during pregnancy
Section snippets
Radiation and measurement in dose units
Radiation, ie, any “energy that comes from a source and travels through some material or through space,”3 can be categorized as either ionizing or nonionizing. Nonionizing radiation “has enough energy to move around atoms in a molecule or cause them to vibrate, but not enough to remove electrons”4; examples include ultrasound waves, visible light, microwaves, and magnetic resonance imaging.
Ionizing radiation “has enough energy to remove tightly bound electrons from atoms, thus creating ions”4
Health impact of high-dose radiation from a nuclear disaster
The International Atomic Energy Agency developed the International Nuclear Events Scale to measure the health significance and environmental impact of all events associated with the transportation, storage, and use of radioactive materials (Table 3).18 Using the International Nuclear Events Scale, radiation exposure events are classified on a scale ranging from 1–7. Both the Chernobyl and Fukushima disasters were classified as a 7, the highest possible rating.
In a radiation disaster, the nature
Effects of radiation in pregnancy
The effects of ionizing radiation on an embryo and fetus can include: pregnancy loss, malformations, neurobehavioral abnormalities, fetal growth retardation, and cancer. The first 4 categories of adverse pregnancy outcomes have a deterministic effect whereby a threshold or No-Adverse-Effect Level (NOAEL) exists; however, once the radiation amount exceeds a certain level, all individuals will be affected. After exceeding the NOAEL, a deterministic effect typically shows a gradient relationship
Radiation exposure on infants and lactating women
Breast milk can become radioactive by a lactating woman's direct exposure to radiation on her breast or ingestion of radioactive pharmaceuticals or food. As with pregnancy, a lactating woman should be cautioned about the potential health effects before using medical diagnostics involving radiation. However, concerns about radiation exposure should not lead women to postpone or abandon critical medical treatment. X-ray exposure resulting from a single diagnostic procedure (eg, mammogram) is far
Protection of pregnant women and fetuses from radiation exposure
Precautionary measures for pregnant women from the effects of radiation-related adverse health outcomes are essentially the same as those for the general public. These measures are based on the following 3 principles: maintaining a safe distance, shielding one's body from exposure, and avoiding ingestion of food and water contaminated with radioactive particles in the air, rain, or soil.68
In case of a large-scale radiation disaster, such as the Fukushima incident, evacuation is the safest
Interventions to enhanced elimination of radioactive materials
The decorporation process, which refers to elimination of radioactive materials from the body, involves prevention of radioactive ion uptake and/or enhanced secretion and excretion of radio nucleotides. The best known measures for decorporation of radioactive iodine is the ingestion of potassium iodine (KI). Once the thyroid is saturated with nonradioactive iodine, it will no longer absorb any more iodine, radioactive or not, even if it is available for uptake. The KI tablets, which contain
Conclusion
In general, the risk of exposure to radiation causing health effects is limited, but can have a significant impact during disasters such as the recent incident in Fukushima, Japan. Public health departments should have detailed radiation reports available as soon as possible in case of a nuclear incident and inform the public of possible health effects and protective measures. Physicians and public health departments should be trained to give objective advice to concerned citizens on the health
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