Effects of X-rays on the fetus

The article was professionally consulted by Specialist Doctor I Vo Cong Hien - Radiologist - Radiology Department - Vinmec Nha Trang International General Hospital.

X-rays during pregnancy affect the fetus is not a question for many pregnant women, because X-rays are a form of radiation and have the potential to affect pregnancy. However, in radiography, the degree of influence of X-rays depends on the effect concentration, gestational age and exposure time.

X-rays are a form of radiation and can affect pregnancy depending on the concentration of effect, gestational age and duration of radiation exposure. Although X-rays can be associated with a risk of cancer, acute leukemia and some other birth defects in the fetus, the risk is quite low. In medicine, when using X-rays for diagnosis, the radiation dose used is very low, many times lower than the dose that is likely to harm the fetus. Specifically:
Risk of miscarriage: With a radiation dose of less than 5 rad (rad: unit of measurement), X-rays do not increase the risk of miscarriage. Besides, every pregnant woman has about 3-15% risk of miscarriage, with or without X-ray; Risk to fetal development: With small radiation doses (even doses of 10-20 rad), the risk of fetal malformations is not significant. The fetus is only likely to grow slowly when x-rayed in the early stages of pregnancy and with radiation doses up to 50 rad; Cancer risk to the fetus: If pregnancy X-rays are taken in the early months of pregnancy and with radiation doses greater than 5 rad, the risk of cancer increases in the range of 0.3 - 1%. However, this risk also existed 0.3% whether the mother was exposed to radiation during pregnancy or not.

According to doctors, each stage of pregnancy has a different degree of influence of X-rays on the fetus. Specifically:
First two weeks of pregnancy: Risk of miscarriage when x-ray dose is greater than 5 rad; 3rd - 8th week of pregnancy: Risk of affecting the fetus when radiation dose is greater than 20-30 rad; After the 20th week of pregnancy: The risk of miscarriage does not increase if an X-ray is taken during pregnancy because the fetus is quite fully developed at this time.

The dose of X-ray that the fetus absorbs (in rad units) in each scan of the mother at the same location, the number of scans has the potential to affect the baby's health with the following levels:
Head: The ability of the fetus to absorb about 0.004/x, to reach the effective dose of 5 rad, the mother must take 1,250 x-rays; Teeth: The fetus's ability to absorb about 0.0001/x. Cervical spine: The ability of the fetus to absorb is about 0.002/x. To achieve an effective dose of 5 rad, the mother needs to take X-rays during pregnancy about 2,500 times; Hands, feet: The ability of the fetus to absorb is 0.001/x. To achieve an effective dose of 5 rad, the mother needs to take 5,000 x-rays; Chest: The ability of the fetus to absorb is 0.00007/x. To achieve an effective dose of 5 rad, the mother needs to take X-rays 71,429 times; Breast: The ability of the fetus to absorb is 0.02/x. To achieve an effective dose of 5 rad, the mother needs to take 250 x-rays; Abdomen: The ability of the fetus to absorb is 0.245/x. To achieve an effective dose of 5 rad, the mother needs to take 20 x-rays during pregnancy; Spine, lumbar: The fetus's ability to absorb is 0.359/x. To achieve an effective dose of 5 rad, the mother needs to take 13 x-rays; The pelvis: The ability of the fetus to absorb is 0.04 / time, to achieve the effective dose of 5 rad, the mother needs to take 125 x-rays.

If the X-ray is taken during pregnancy only once, there is no risk of harm to the unborn baby. And X-ray doses less than 5 rad do not increase the risk of harm to the fetus because the dose of X-rays that can cause malformations in the fetus is up to 15 rad. Therefore, pregnant women still need regular antenatal check-ups to check their health and screen for abnormalities during pregnancy.
BSCK I Vo Cong Hien has many years of experience in the field of imaging, especially in diagnostic ultrasound for general abdominal diseases, advanced cardiac - vascular, obstetrics and gynecology. Doctor Vo Cong Hien used to work at the Imaging Department of the University of Medicine and Pharmacy Hospital - Hoang Anh Gia Lai before working at the Imaging Department of Vinmec Nha Trang International General Hospital.