Ionizing radiation for maternal medical indications.

Ionizing radiation should be considered an avoidable exposure although all pregnant women receive some radiation from their environment. The potential effect of ionizing radiation on the fetus is determined by the dose and the timing of the exposure with growing interest in the potential risks of transgenerational effects of radiation as an epigenetic phenomenon. High dosage exposure is very unlikely in routine situations such as occupational, diagnostic, or therapeutic exposures. Individual diagnostic radiation procedures (fetal dosage <50 mGy), are not associated with any increase in lethality (miscarriage or stillbirth), genetic damage, teratogenicity, growth impairment, mental retardation, or sterility. More recent modeling has suggested that a 10 mGy fetal dose is associated with an excess risk of childhood cancer risk as low as 1 in 4545, well below historical estimates.When the mother's condition necessitates diagnostic radiation it is necessary to balance the risks of the procedure with the benefits to be gained. As almost all diagnostic imaging involves doses below the 50 mGy threshold, clinically indicated investigations should not be withheld because of concerns regarding fetal radiation exposure. Even radiotherapy directed away from the abdomen or pelvis may be considered during pregnancy, if the benefits outweigh the risks and no suitable alternative is available.