Does CT or X-ray examination during pregnancy lead to fetal malformation?

Pregnant expectant mothers are most concerned about the fetus in their womb. Whether they can develop healthily affects the hearts of expectant mothers all the time.

With people’s attention to fetal health and the continuous development of medical technology, The various medical examinations exposed during pregnancy are increasingly diversified. While these examinations provide physical information, the safety issues during use are also concerned by expectant mothers. Some expectant mothers are very taboo to CT or X-ray films, and they are worried that the radiation exposed during the examination will affect the health of the fetus and even lead to fetal malformation.

Is this really the case?

[Radiation] Is it what?

Radiation is a physical term, which can be divided into two categories according to its ability to ionize atoms and destroy chemical bonds: ionizing radiation and non-ionizing radiation.

Non-ionizing radiation has weak energy and no ionization capability. For example, electromagnetic waves emitted by electronic equipment such as mobile phones, computers and microwave ovens all belong to this category. So far, relevant scientific research has not found evidence to prove that non-ionizing radiation is harmful to human body.

The radiation we are discussing here refers to ionizing radiation that has ionizing ability and may affect human health.

Understanding X-ray

The most important ionizing radiation that we can come into contact with in our daily life is X-ray.

X-ray has long wavelength and large energy, and has penetrating and ionizing effects. When excessive X-ray irradiates biological organisms, biological cells can be inhibited, destroyed and even necrotic.

What is the indicator to measure radiation?

The common radiation dose units are Gy and Sv. Gy is the average energy of ionizing radiation received by a unit mass substance, and Sv is the degree of harm to organisms caused by various kinds of ionizing radiation. Studies have found that when human beings are irradiated with a dose of 4 Sv, the death rate reaches 50%.

Effects of Radiation on Human Body

Radiation must reach a certain dose to cause damage to human body, which is called a threshold. Under this dose, it is regarded as not harmful to human body. The more you exceed the threshold, the higher the severity.

For example, the dose for permanent infertility of men is 3.5 Gy at a single time, while that for permanent menopause of women is 2.5 ~ 6 Gy at a single time. The damage threshold for pregnant women and fetuses can be referred to the attached table.

The essence of X-ray is a kind of high-frequency and high-energy electromagnetic wave, which will not adhere to the human body like radioactive substances in nuclear leakage accidents to produce continuous effects. Therefore, there is no residual problem after X-ray inspection. When the inspection is terminated, the radiation disappears and will not continue to affect the human body.


Influence on fetus dose threshold (mSv) during irradiation periodFetal death (abortion) preimplantation (fertilization ~ 9 days) 100Deformed organ formation period (2 ~ 8 weeks) 100Brain growth retardation fetal period (8 ~ 25 weeks) 120Cancer Risk Full Period 10

Effect of Radiation on Development of Fetus


The dose of the fetus of the examination itemAbdominal CT8 mSvChest CT0.06 mSvChest X-ray (positive) < 2 µ SvAbdominal X-ray (positive) 170 µ SvLumbar X-ray (anteroposterior and lateral) 350 µ Sv

Radiation dose of fetus during CT and X-ray examination of pregnant women

Note: 1 mSv = 1000 µ Sv

Frequently Asked Questions about CT or X-ray Examination

1. 会导致胎儿智障吗?

According to the data in the above table, even if the expectant mother undergoes abdominal CT examination, the radiation dose to the fetus is only 8 mSv, which is far from 50 mSv (abortion and teratogenesis will not occur below 50 mSv), not to mention the threshold of 200 mSv, which has an intellectual impact on the fetus.

2. 会导致白血病、癌症吗?

Ionizing radiation is one of many factors that lead to leukemia. In fact, leukemia can only be caused by long-term exposure to large doses of ionizing radiation.

According to statistics, if the fetus receives a radiation dose equivalent to about 500 chest X-rays at a time, the risk of cancer in his life will increase by only 2% at most, but the risk of cancer in human life will be 40-50%, so there is no need to be too nervous.

3. 对胎儿还会造成哪些影响?

    First 2 weeks of conception: Receive radiation, The most serious impact on the fetus is the death of the fetus. At this stage, the fetus consists of only a few cells. Radiation damage to a cell will cause the death of the embryo. For surviving embryos, No matter what dose of radiation it received at that time, Radiation-related birth defects rarely occur. 2 ~ 18 weeks of pregnancy: When receiving large doses of radiation (exceeding the dose equivalent to 500 chest X-rays), Will lead to birth defects, In particular, the brain will be greatly affected. From 18 weeks of conception to birth: Fetuses will hardly undergo radiation-induced health changes unless they receive extremely large doses of radiation (far more than the dose equivalent to 5,000 chest X-rays). Postpartum 26 weeks: Infants during this period are no longer as sensitive to radiation as they were in their newborns, so radiation will not affect their health and will only slightly increase their risk of cancer in their lifetime.

4. 辐射怎么防护?

As a patient, radiographers can be asked to give shielding protection during examination, such as wearing lead clothing, lead scarf, lead cap, lead glasses, etc. to protect important organs.


X-ray examination can provide very important reference information to doctors under certain conditions. Even in pregnancy, doctors may suggest you to have X-ray-related examination.

Most X-rays of the limbs, head and chest do not directly expose the reproductive organs to radiation and, if properly protected, will not affect the fetus. If you are pregnant or planning to become pregnant and are ready for an X-ray examination, please be sure to inform the radiologist and seek their advice.

For expectant mothers who are already pregnant, if they need X-ray examination, remember to ask the examination technician to give you suitable lead clothing to cover important organs. In addition, if you have undergone similar examination recently, you can communicate with the radiologist to avoid repeated examination.

Many women who have undergone X-ray-related examinations are told not to conceive within six months after the examination. In fact, the situation is far less serious, because these statements are advice given by doctors for the greatest safety considerations. It is very safe to prepare for conception after three months of examination.

Responsible Editor: BruceLi