Chest X-ray is a commonly used X-ray examination method. It utilizes the properties of penetrating, fluorescent and photographic effects of X-rays to form an image of the human body on the screen. Due to the difference in density and thickness of human tissues, when X-rays penetrate different tissues of the human body, the X-rays are absorbed to a different extent, so the amount of X-rays arriving on the screen varies, forming black and white images with different contrasts, providing a basis for clinical diagnosis. Ionization is caused by the penetrating radiation of high-energy particles causing electrons to be expelled from atoms, and it causes damage to cells mainly through its effect on DNA molecules, leading to a variety of health hazards. The deposition of energy by ionizing radiation acting on the tissues and organs of the body is a random process, and even at fairly low dose levels, if the energy is deposited in a critical target area of a cell, it can lead to cellular changes or death. However, if the X-ray shot is within tolerance, the effects are generally minimal. In the last decade, due to improvements in X-ray equipment, the use of high-kilovolt technology, image enhancement technology, high-speed intensifying screens, and fast X-ray-sensitive films, the amount of X-ray radiation has been significantly reduced, and the potential for radiation damage is becoming less and less. Pregnant women are worried about X-rays, and often are in the case of not knowing that they are just pregnant, X-rays, and thus worried about fetal radiation safety, have asked for abortion, is it necessary? Exposure of embryos to free radiation is mainly due to the possibility of embryonic death, miscarriage, fetal congenital malformations, mental retardation, microcephaly, fetal growth retardation, resulting in these embryonic injuries are mainly related to the dose of radiation and the period of the embryonic stage of development, which must be more than the safe dose will be possible, which we call the threshold dose phenomenon. As for the increased chance of cancer or blood cancer in childhood, it is generally believed that this is a non-threshold dose phenomenon, which is theoretically caused by exposure to radiation, but it is generally believed that the dose must be higher than 20 rads. It has been documented that if one sibling develops blood cancer, the other siblings have a 1:720 chance of developing blood cancer, which is much higher than the 1:6000 chance of potential cancer risk from diagnostic radiation. The early stages of pregnancy, i.e., prior to embryo implantation or organogenesis (1-14 days of gestation) are the periods when the embryo is usually less likely to be harmed by free radicals. This early period of embryonic development is all-or-none. According to animal studies, the dose of radiation must be greater than 1.5 to 2.0 Gy to cause embryonic death. If the fetus does not die and continues to develop, the chance of congenital anomalies is the same as in normal embryos. The most sensitive period for radiation damage to the developing embryo is 22 days after conception, when the radiation dose must be higher than 20 rad to cause congenital anomalies in the embryo. For fetal growth retardation, the radiation dose must be higher than 25-40 rads. As for fetal mental retardation and severe microcephaly, the most susceptible time for radiation damage usually occurs during 8-15 weeks of fetal development, followed by 16 weeks of gestation. In general, during pregnancy, if an abdominal X-ray is taken, the radiation dose is about 122-245 millirad or the equivalent of a burst of 0.122-0.245 rad, and the dose of a chest X-ray is about 0.02-0.07 millirad, while the dose to the fetus from a small dental X-ray is even more negligible, and it is far away from the threshold for safe radiation dose to the fetus, which is 5000 millirad. 5000 millirad, a far cry. Therefore, there is no cause for concern unless the fetus is being treated with radiation, such as high-dose irradiation for cancer. In addition, the radiation dose from medical scans during pregnancy, such as bone scans, liver and gallbladder scans, heart and lung scans, brain scans, etc., is within the safe range. Generally speaking, the exposure dose of the embryo in the womb during the first 12 weeks of pregnancy is higher than that during the middle and late stages of pregnancy. The only exception is the radioactive iodine thyroid scan, which is a very high dose of radioactive iodine ingested by the fetus’s thyroid gland after the 11th week of pregnancy and can cause damage to the fetus’s thyroid gland. Pregnant women who have medical reasons for undergoing computed tomography scanning of all organs of the body receive radiation doses that are within the permissible thresholds for safe radiological doses. Nevertheless, women who are not using contraception are advised to avoid undergoing X-rays after ovulation, and if they must, they should protect their abdomen with a lead plate. There is a famous “10-day rule” that suggests that unless there is an emergency, women should choose to have their X-rays taken within 10 days of the start of their menstrual cycle, so that they do not have to worry about what to do if they become pregnant. It has been reported that iodine-containing contrast agents may cause hypothyroidism in some newborns. Pregnant women who undergo angiography or computed tomography using iodine-containing contrast agents are advised to have their newborns screened for thyroid function. As for the safety of fetal MRI, to date, there have been no reports in the literature of risks or sequelae of MRI that would jeopardize fetal safety. In fact, MRI can be safely performed at any time of pregnancy if it is medically necessary. However, the National Radiation Protection Society (UK) recommends that MRI should be avoided in the first trimester of pregnancy, which is a critical time for fetal organ development. In addition, the rate of miscarriages is higher in the first trimester (15%), making MRIs an easy scapegoat. As to whether the rapid resonant electromagnetic flow noise generated by MRI scanners can have a hearing effect on the fetus in utero, there have been two reports from the United Kingdom showing that there is no fetal hearing damage. The need for contrast agents MRI contrast agents usually work to alter the magnetic field effects of nearby hydrogen nuclei, rather than through radio-opaque drugs are classified as Class C, and no cases of congenital anomalies have been reported. Understandably, some people are concerned about the safety of contrast agents and recommend against their use. In fact, these contrast agents are commonly used in neonatal and pediatric radiology, and according to the recommendations of the American College of Radiology, they can be used in pregnant women and fetuses after in-depth counseling to inform them of the benefits and potential risks of an MRI examination. The European Society of Genitourinary Radiology Communication Guidelines state that contrast agents may be used when there is a medical reason for a pregnant woman to have an MRI. Contrast agents are used at the lowest possible concentration of the required dose and are not recommended for use in pregnant women with renal dysfunction due to the potential for nephrogenic systemic fibrosis. MRI is not recommended for women with allergic reactions to contrast media, spatial claustrophobia, pacemakers, metallic implants in the body, or surgical metal clips. The American College of Obstetricians and Gynecologists (ACOG) recommends the following for pregnant women undergoing diagnostic radiological testing: Women who are accidentally exposed to radiation during pregnancy should be counseled in detail to reassure them that no single diagnostic radiological test can cause fetal radiation damage, especially if the radiation test is less than 5 rads, which is less than 5,000 millirad safe doses. Pregnant women should not refuse to undergo the necessary diagnostic radiological tests for fear of fetal harm, but we recommend that if there are alternatives, ultrasound or MRI, which do not have the potential to cause fetal harm, should be given preference. When a pregnant woman undergoes a diagnostic radiation test, she should consult a radiation protection physician about the radiation dose. Pregnant women should not be treated with radioisotopes of iodine. Safety in Pregnancy If there is a diagnostic need for a diagnostic radiographic exam that requires the use of a contrast agent, it can be used when the benefits outweigh the harms and is unlikely to cause potential fetal harm. Just pay attention to regular labor and delivery tests, if the labor and delivery tests are fine, the fetus should just not be affected, don’t worry too much. If you receive ionizing radiation during early pregnancy, do not dare to say that the child certainly has or does not have an effect, in the case of very much want the child, it is recommended to do a good job of regular checkups, such as Down’s syndrome screening, four-dimensional, and so on. Even if abnormalities are found, terminate the pregnancy, and it is best if there are no abnormalities.