RADIATION SAFETY MANUAL
Section 12: Radiation and Pregnancy
| 12.1 |
Ionising radiation, being damaging to tissue in large enough quantities, is potentially harmful to the foetus. The risks however, for diagnostic and occupational levels of radiation exposure, are very small. The greatest risk of mental retardation, occurs in the 8-16 week period of a pregnancy, ie after most pregnancies are known. The risk of all adverse effects is of the order of 1 per 10,000 per mGy dose to the foetus, ie a risk of approximately 0.01%/mGy. This compares to normal occurrence of congenital defects of approximately 5%.
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| 12.2 |
Female staff working with radiation or radioactive material are naturally concerned as to the well-being of their foetus if they fall pregnant and continue to work in the same situation until the pregnancy is recognised. The National Health and Medical Research Council considers that separate dose equivalent limits are not necessary, assuming that a pregnancy would not go unrecognised for more than two months. When a pregnancy is confirmed, however, arrangements should be made to ensure that the woman works only under such conditions that it is most unlikely the exposures during the remainder of the pregnancy will exceed 3/10ths of the pro-rata annual dose equivalent for radiation workers. Staff working in areas where radiation is used routinely may request special radiation exposure monitoring (usually TLD) whilst they remain at work. (Contact the Building/School RSO for details).
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| 12.3 |
Exposure of the embryo or foetus of a patient who is subsequently found to be pregnant often creates unnecessary worry in the mind of the patient or her medical practitioner. In fact, the risks of radiation exposure, even at relatively large levels, is very small compared to the normal risks of pregnancy. Information in the literature suggest that absorbed doses of 20 mGy would pose no risk and unqualified reassurance may be given to the patient. This is not to say, however, that doses of this order may be deliberately administered to a pregnant patient. It must be stressed that this applies only to accidental exposures, where the alternative may be termination of the pregnancy - a quite unwarranted step in nearly all cases.
All cases of accidental irradiation of a foetus or embryo should, for the sake of all concerned, be referred to the University Radiation Safety Officer or a radiologist.
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| 12.4 |
Staff who are concerned about their own circumstances are welcome to contact the University Radiation Safety Officer for further information. |
