[Radiodiagnosis and irradiated pregnancies].

Abstract

An X-ray examination can sometimes be performed during the first few days of pregnancy. To prevent these accidental irradiations of the fetus, women must receive specific information about radiation effects, the ten Day Rule must be respected, and the physician must choose a non irradiating technique. X-ray examination may be performed in an emergency, especially if the examination is far from the pelvis. The radiologist must optimize the constants and decrease the number of films. The dose received depends on mAs, but other parameters are necessary for calculation (film source distance, kV, filtration...). For computed tomography, slice thickness, and interval between slices are taken in account. The dose received reaches a maximum after three axial sections, but is higher for a given area, than with conventional radiography. The irradiation effects depend on the fetal dose and the stage of pregnancy. Before implantation, the fetal dose is either ineffective or induces a miscarriage. During organogenesis, between the second and 16th week, doses exceeding 500 mGy can cause death of the fetus, malformations or growth retardation. We consider that when the dose is less than 100 mGy, they are no reasons to terminate the pregnancy. MRI does not seem to be dangerous for the course of pregnancy. No studies have demonstrated any teratogenic effects with intense magnetic fields.