ACOG Committee Opinion, Number 299, September 2004, Reaffirmed 2009 (Replaces No. 158, September 1995)

Undergoing a single diagnostic X-ray procedure does not result in radiation exposure adequate to threaten the well-being of the developing preembryo, embryo, or fetus and is not an indication for therapeutic abortion. When multiple diagnostic X-rays are anticipated during pregnancy, imaging procedures not associated with ionizing radiation, such as ultrasonography and magnetic resonance imaging, should be considered. Additionally, it may be helpful to consult an expert in dosimetry calculation to determine estimated fetal dose. The use of radioactive isotopes of iodine is contraindicated for therapeutic use during pregnancy. Other radiopaque and paramagnetic contrast agents have not been studied in humans, but animal studies suggest that these agents are unlikely to cause harm to the developing human fetus. Although imaging techniques requiring these agents may be diagnostically beneficial, these techniques should be used during pregnancy only if potential benefits justify potential risks to the fetus. Various imaging modalities are available for diagnostic use during pregnancy. These include X-ray, ultrasonography, magnetic resonance imaging (MRI), and nuclear medicine studies. Of these, diagnostic X-ray is the most frequent cause of anxiety for obstetricians and patients. Much of this anxiety is secondary to a general belief that any radiation exposure is harmful and will result in an anomalous fetus. This anxiety could lead to inappropriate therapeutic abortion and litigation. Actually, most diagnostic radiologic procedures are associated with little, if any, known significant fetal risks. Moreover, according to the American College of Radiology, no single diagnostic X-ray procedure results in radiation exposure to a degree that would threaten the well-being of the developing preembryo, embryo, or fetus (1). Thus, exposure to a single X-ray during pregnancy is not an indication for therapeutic abortion (2, 3). Some women are exposed to X-rays before the diagnosis of pregnancy. Occasionally, X-ray procedures will be indicated during pregnancy for significant medical problems or trauma. To enable physicians to counsel patients appropriately, the following information is provided about the potential risks and measures that can reduce diagnostic X-ray exposure.