Weekly Chronicle of Pregnancy (13): Pregnant, can I still do CT?

Miss Zhou’s friend called Dr. Tian anxiously for advice:

Judging from the performance, it seems that it is between heavy and light, but it can also be observed and taken measures if there is further situation. However, dizziness and vomiting cannot rule out the possibility of more serious problems. Early examination seems to be conducive to taking early measures to reduce risks.

As a result, the question arises, will the radiation from head CT affect the baby? How to choose between the potential risks of mother and baby?

It is rare to have such [a little back] situations as friends, but I believe many expectant mothers will also encounter similar troubles:

Radiation is present in many of the various medical examination methods, such as X-rays and CT, which are the most commonly used. Are these examinations strictly prohibited during pregnancy? If it has to be carried out, will it affect the baby?

Why does radiation affect babies?

The radiation produced by X-ray and CT examinations is called ionizing radiation. Its characteristic is that its energy is so large that it can ionize atoms, directly damage cells or change DNA structure, causing harm to human body.

Dr. Tian, a neurosurgeon, gave his friends advice on [continuing to observe] after thinking, but I was more interested in this [decision-making] process and started to ask 100,000 reasons again.

The effect of ionizing radiation on babies can be evaluated from two aspects: 1. The amount of radiation; 2. The size of the baby, that is, the pregnancy stage.

Talking about harm without dose is all hooliganism.

First, let’s talk about the radiation dose.

Dr. Tian found a lot of information. After studying hard all night, I finally understood-the most important question is:

How many doses of ionizing radiation will affect the baby in the belly?

Scientific research has pointed out that the radiation dose that will have an intellectual impact on the fetus is between 200 mGy and 400 mGy.If the ionizing radiation is controlled below 50 mGy, there will be no adverse consequences such as abortion, teratogenicity or influence on fetal intelligence.

So, is 50 mGy a what concept? Is it large or small compared with our daily X-ray and CT examinations?

Miss Zhou found a form explaining the impact of various examinations on the baby in her belly. Let’s take a look at it together:

Estimated doses of fetal exposure to commonly used medical radiological examinationsMethods of examination Fetal exposure doseChest plain film (one shot in front and one shot in side) 0.0002 ~ 0.0007 mGyAbdominal plain film (single irradiation) 1 mGyHip plain film (single irradiation) 0.07 ~ 0.2 mGyHead or chest CT scan < 10 mGyAbdominal or lumbar CT scan 35 mGyPelvic CT scan 2.5 mGy

It is easy to see from the table that the amount of radiation received by the baby for these commonly used examination items is less than 50 mGy.

Miss Zhou’s friend, who wants to have a head CT scan, has to do it five times in a row, which may cause harm to the baby. However, if she wants to have a chest radiograph (i.e. A chest X-ray), she has to do it more than 70,000 times in a row, which may cause abortion.

Gao Hui, deputy chief physician of Obstetrics and Gynecology Department of Beijing Tiantan Hospital, reminded expectant mothers that X-rays travel in a straight line, so as long as it is not to take abdominal plain films, a lead plate can be placed on the abdomen of expectant mothers to minimize the side effects of ionizing radiation.

Effects beyond radiation dose

In addition to the radiation dose, the impact of radiation on the baby in the belly is also different at different stages of pregnancy.

Miss Zhou is in < < this child, can she stay? > > The article mentioned:

    Pregnant for 0 ~ 4 weeks: This is a [complete or non-existent stage]. In this stage, if the baby is injured by ionizing radiation, it is either safe or killed directly, and there will be no [persistence with injuries]. 5 ~ 8 weeks of pregnancy: This is the early stage of cell differentiation and the fetus will be more sensitive. However, as long as the dosage mentioned above is controlled, scientific research is considered safe. 8 ~ 15 weeks of pregnancy: This is the period when radiation has the greatest impact on the baby’s intellectual development, but there is no need to panic too much.

Scientists’ research on pregnant women and fetuses after Japan’s atomic bomb explosion during World War II showed that during this period, the radiation level was as high as 1,000 mGy, and 40% of fetuses’ intelligence decreased. If the radiation level reaches 1,500 mGy, the proportion of fetal intelligence decline will rise to 60%.

Generally speaking: after the early pregnancy, the bigger the gestational weeks, the radiation dose that can produce harm to the baby is also gradually increasing. In other words, after the sensitive period, the baby’s resistance to radiation is also getting stronger and stronger.

Moreover, in the environment in which we live, there is ionizing radiation from nature. This is also called [background radiation] or [background radiation], whether you are at home, going to the beach to bask in the sun, taking a plane… the average person on earth receives about 2.4 mGy of [background radiation] a year, which is equivalent to a pelvic CT scan.

Therefore, expectant mothers need not turn pale at the mention of [radiation] during pregnancy.

Can pregnancy preparation be exposed to radiation?

There must be expectant mothers to ask, the above is all about the examination after pregnancy, then if X-ray examination is done before pregnancy, does contraception need to be carried out for a period of time?

Dr. Gao Hui said that there is no data to support this problem at present, but usually the development time of an egg is about 3 months. If you are worried about possible effects, it is better to use contraception for 3 months. After all, no psychological burden will be beneficial to pregnancy.

Having said so much, the main reason is to relieve people’s unnecessary worries. However, the harm of ionizing radiation is relatively certain. For expectant mothers:

When exposure to ionizing radiation can be avoided, it should be actively avoided, especially during the first 3 months of pregnancy.

At this time, the expectant mother who is already pregnant is also expected to ask, if she has had X-ray and CT examination before pregnancy, and there is no contraception, she is already pregnant, do she want to have an abortion? This question is that Miss Zhou used to be in < < this child. Can she stay? > > answered in detail.

Dr. Gao Hui not only agreed with Miss Zhou’s point of view, but also raised a question that requires expectant mothers to think carefully:

The loss outweights the gain if the inspection that should be done is not done.

Finally, use a story to sum up the girl’s point of view.

Miss Zhou heard a true story:

People who understand science will point out that nuclear magnetic resonance examination does not belong to ionizing radiation. This issue, including non-ionizing radiation such as mobile phones and computers, will be discussed carefully later. However, this real case reminds expectant mothers all the time:

Radiological examination during pregnancy is actually the choice of “the lesser of the two evils”.

Remember, the mother’s life is always the first. We should really try our best to avoid all kinds of harmful radiation during pregnancy, but we must not go to extremes. Necessary examinations must be done.

Responsible Editor: BruceLi Zhang Jingyuan