CT uses ionizing radiation from X-rays to complete the examination, and X-rays have certain effects on the human body. The organs of the fetus are still developing in early pregnancy and are more sensitive to X-rays. X-rays may affect its development, leading to malformations, restricted development and, in serious cases, embryonic death. the effect of X-rays is usually related to the week of pregnancy. if it is within 1-14 days of pregnancy X-rays have less effect; if the pregnant woman is more than 14 days pregnant, she should try to avoid X-rays. In addition, the effect of X-rays on the fetus is greater if it is within 2-4 weeks, because this is the period when the brain and other important organs are taking shape. Of course, during a woman’s pregnancy, if it is a very necessary situation and a CT examination must be performed, it can be done under the protection of a lead suit. In non-essential cases, CT exams should be avoided or replaced by ultrasound and MRI.