Radiation exposure during pregnancy

A fetus may accidentally be exposed to radiation when an individual is unknowingly pregnant or or does not inform the medical staff prior to a medical examination involving radiation. Depending on the requirements in the medical examination, it may also not be possible to prevent the fetus from radiation exposure.

If this is the case it can cause anxiety and concern even if the radiation exposure in most cases is so low that the risk from it is negligible compared to other risk factors.

General

X-rays are a form of electromagnetic radiation just like visible light, ultraviolet radiation and microwaves, but they have much more energy and can therefore penetrate most materials. When penetrating living tissue, the x-ray radiation can damage the cells and their DNA.

A fetus is more sensitive to the harmful effects of radiation than an adult because, among other things, the cells of the fetus divide more rapidly and its tissues are in rapid growth.

Effects on fetus health

The possible damage to the cells of the fetus by X-ray radiation depends on the intensity of the radiation and on the stage of pregnancy at which radiation is performed. The risk is higher in the first trimester of the pregnancy when the organ formation occurs, but lower in the second and third trimesters. The risk of mental retardation is primarily between week 16 to 25 of pregnancy when the central nervous system of the fetus is developing.

Harmful effects of radiation on the fetus may include miscarriage, malformation, mental retardation or cancer later in life.

According to guidelines published in 2000 by the International Commission on Radiation Protection, which are based on best available knowledge and data of biological effects of ionizing radiation, doses of radiation below 100 mGy do not cause significant increase in miscarriage or malformations.

Such radiation doses also do not significantly increase the risk for mental retardation. The risk of cancer later in life due to radiation in the womb is stated to be similar to the risk of radiation in the first years of life.

X-ray examinations

The fetus in the womb should not be exposed to radiation when X-raying the mother's upper body, e.g. during lung examination, dental X-rays, and throat and upper limbs examinations

If X-rays are taken of the lower torso, such as during abdominal examination, the lumbar spine and sacrum, pelvis and urinary tract, the fetus is exposed to some radiation, but generally the radiation is very low and the risk to the fetus is negligible.

The fetus is exposed to more radiation if fluoroscopy is used for X-ray examinations of the lower torso, for example for examinations of the gastrointestinal tract, colon and CT examination of abdominal organs.

If it is considered necessary to conduct the study despite pregnancy, the procedure should be performed with utmost care so that the radiation dose to the fetus will not exceed what is strictly necessary

Extensive measurements of patient radiation during various common x-ray examinations have been carried out both abroad and in Iceland. Based on these, it is possible to estimate how much radiation the fetus in the womb will be exposed to during these studies. Radiation exposure of patients varies greatly from site to site and from patient to patient.

Summary

Due to the possible harmful effects of radiation, one of the main principles of radiation protection is that the radiation exposure of a patient should not be not more than necessary. This is especially emphasized in the case of pregnant patients.

According to guidelines published in 2000 by the International Commission on Radiation Protection, radiation doses below 100 mGy do not cause a significant increase in miscarriage or birth defects.

Such radiation doses also do not significantly increase the risk for mental retardation. The risk of cancer later in life caused by radiation in the womb is stated to be similar to the risk of radiation in the first years of life.

In most cases where a fetus could be exposed to radiation during a medical examination, the radiation is so small that the risk from it is negligible compared to other risk factors.