It is possible to have an X-ray or even a CT during pregnancy. Generally the radiation doses from X-rays or CTs done today are well below what parents need to worry about, so the effect on pregnancy is negligible. This is not for me to say, most of the European and American literature as well as internationally accepted views are also true, here are the recommendations of the American College of Obstetricians and Gynecologists in 2009, which I will briefly describe. Common radiologic exams include x-rays, computed tomography (CT) scans, magnetic resonance imaging (MRI), and ultrasound. Only X-rays and CTs are radioactive. The effects of radiation on pregnancy have been observed in animals and survivors of nuclear explosions. The negative effects of radiation include: 1) deformities or mental retardation; 2) cancer; and 3) mutations in germ cells, which may have genetic effects on the next generation. The 8-15th week of pregnancy is the most sensitive period to radiation. If a pregnant woman is exposed to extremely high doses of radiation during this period (20RAD or more), the risk of the fetus suffering from malformations or mental retardation increases significantly, and the higher the dose, the greater the chance. However, if you are exposed to radiation during this period, doses of no more than 5 RAD or more are unlikely to affect the fetus. There is no scientific evidence of malformations caused by radiation before the eighth week of pregnancy or after the 25th week! There is no definitive answer as to whether exposure to radiation during the fetal period increases the chances of cancer, but if it does it is very unlikely. Some data show that fetal exposure to 1-2 RAD increases the chance of developing blood cancers by a factor of 1-2 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 1/2000. If you abort a child for this risk, you would need to abort 1999 healthy children to prevent one blood cancer, and this 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 requires a contrast agent to make the image clearer; the contrast agent used in MRI has been shown to increase the chances of miscarriage in animal studies, but this is only likely to happen at 2-7 times the dose recommended for humans, and so the so-called enhanced MRIs (which require intravenous contrast) are usually done. NMR (which requires intravenous contrast agent) is also safe during pregnancy. Nevertheless, it is currently recommended to wait until after delivery if you can. The contrast agent used in CT is also basically safe, but since there have been sporadic reports that it can lead to natural hypothyroidism, it should be avoided if possible, or wait until after delivery. It was mentioned that it is safe for the fetus to be exposed to no more than 5 rad rad during pregnancy, but as you can see from the table, it’s not easy to reach 5 rad. As you can see from this table, it is not easy to reach 5 rads. If one chest X-ray counts as 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 would have to be taken 50 times before they start to be dangerous. Tomography (CT) is comparatively a much higher dose of radiation, but even an abdominal CT would not yet exceed the threshold of 5 rads. To summarize, here are the current recommendations: 1. Women should be informed that any single radiological examination during pregnancy will not have an effect on the fetus. More specifically the dose of radiation exposed does not exceed 5 rads or more is not likely to increase the chance of fetal malformations or miscarriage; 2. Pregnant women should not be prevented from having the necessary X-rays because of concerns about the possible effects of radiation. However, during pregnancy, if appropriate, consideration should be given to replacing CT or X-rays with non-radiation tests such as ultrasound or MRI; 3. Nuclear magnetic resonance (NMR) and ultrasound do not have any effect on the health of the fetus; 4. During pregnancy, if a pregnant woman needs to undergo multiple or more radiation-emitting tests, she may consider having a radiologist consult her for help in calculating and determining the dose of radiation that the fetus will be exposed to after the test; 5. Radioactive isotopes of iodine are not allowed to be used for treatment during pregnancy. Radioactive iodine isotopes should not be used for therapeutic purposes during pregnancy (this is true for some patients with methotrexate); 6. Intravenous contrast agents for CT or MRI enhancement during pregnancy are unlikely to have any effect on the fetus, but nonetheless, they should be used only when they are more likely to be beneficial to the diagnosis and to the mother’s health than to be harmful. Finally, patients often ask if there is a waiting period after X-rays or CT for either the man or the woman before they can get pregnant, but there is no such thing, as they can be taken even when they are pregnant, let alone before. What about when you are breastfeeding? Of course you can, and you don’t have to stop breastfeeding after an enhanced CT or MRI, because the amount of contrast media used today that appears in breast milk is very small, just like the medications that most mothers take, so you don’t have to stop breastfeeding for that reason.