This is a question that is occasionally asked by outpatients and internet users, and the answer is YES! The radiation doses from the X-rays or CTs that are currently being done are far below the range that parents need to worry about, so the effect on pregnancy is negligible. This is not my word, as is the majority of European and American literature and internationally accepted opinion. Here are the recommendations from the American College of Obstetricians and Gynecologists 2009, which I will briefly describe. Common radiology tests include X-rays, CT, MRI, and ultrasound. These are the only ones that have radiation. The effects of radiation on pregnancy have been observed mainly in animals and in survivors of nuclear explosions. The negative effects of radiation include: causing malformations or mental retardation, causing cancer, causing mutations in germ cells, and thus may have genetic effects on the next generation. The risk of fetal malformation or mental retardation is significantly higher with higher doses. However, if the exposure to radiation during this period does not exceed a dose of 5 RAD or more, it will not affect the fetus. There is no scientific proof that radiation causes malformations before the eighth week of pregnancy and after the 25th week! There is no clear answer to the question of whether exposure to radiation during the fetal period increases the chance of cancer, but if so, the likelihood is very low. Some data show that fetuses exposed to 1-2RAD (Rad) have a 1-2 times higher chance of developing blood cancers later in life. In other words, the chance of the average child developing blood cancer is about 1 in 3000, while the chance of a fetus exposed to radiation is about 1 in 2000. To abort a fetus for this risk would require the abortion of 1999 healthy children to prevent one blood cancer, and is not recommended. Ultrasound, or ultrasound, is radiation-free and safe for the fetus. MRI, or magnetic resonance imaging, is also radiation-free and basically safe, but sometimes a contrast agent is needed to make the image clearer; the contrast agent used in MRI has been shown to increase the chance of miscarriage in animal studies, but only at 2-7 times the recommended human dose, so the so-called enhanced MRI is generally done. MRI (which requires intravenous contrast) is also safe during pregnancy. Nevertheless, it is advisable to wait until after delivery if possible. The contrast agent used for CT is also generally safe, but because there are sporadic reports of low thyroid function at birth, it should be avoided if possible or waited until after delivery. In summary, the following is the current advice: 1. Women should be informed that any single radiology test performed during pregnancy will not have an effect on the fetus. More specifically, exposure to radiation doses of no more than 5 rads will not increase the chances of fetal malformation or miscarriage. 2. Pregnant women should not be prevented from undergoing necessary X-ray examinations because of concerns about the possible effects of radiation. However, if it is appropriate during pregnancy, consider using non-radiation tests such as ultrasound or MRI instead of CT or X-ray as much as possible. 3. MRI and ultrasound have no effect on the health of the fetus. 4. If a pregnant woman needs to undergo multiple tests or examinations with radiation, she can consider having a radiologist consult to help calculate the radiation dose to which the fetus may be exposed after the examination. 5. Isotopes of radioactive iodine cannot be used in treatment during pregnancy (this is for some patients with nail resistance). 6. MRI is unlikely to have any effect on the fetus, but nevertheless, contrast should be used only when it is more beneficial than harmful to the diagnosis and the mother’s health. Lastly, patients often ask if the man or woman has to wait a while to get pregnant after an X-ray or CT. What about during breastfeeding? Of course, you don’t have to stop breastfeeding because you have had an enhanced CT or MRI, because the amount of contrast agent used in breast milk is very small, just like most of the medications mothers take, and only a small amount appears in breast milk. I hope this information is helpful to some confused mothers-to-be. It is not easy to reach 5 rads, if one chest x-ray is 0.1 mrad, it would take 50,000 chest x-rays to have a possible effect on the fetus. The higher dose abdominal x-rays also require 50 shots before they start to be dangerous. Tomography (CT) is a much higher radiation dose, but even a CT of the abdomen would not exceed the 5 rad threshold.