Practical obstetrics info for your women's healthcare practice

Can a CT Scan Be Used In Pregnancy?

CLINICAL ACTIONS:

If a CT (computed tomography) scan is being considered or has been ordered and the patient is pregnant, consider the following questions

  • Would a CT be ordered if the patient was not pregnant?

If the answer to the above is ‘yes’

  • Is there another option available that would provide the equivalent information on which to base management?
    • If yes
      • Consider an MRI, which is a safe alternative to CT imaging in cases where they are equivalent for the diagnosis in question
    • If no, and there is not an equal or better alternative
      • CT scan should be performed
      • Do not withhold associated contrast material if clinically indicated
  • In addition to a discussion of the risks and benefits with the patient, there are additional resources that can be accessed if necessary, including
    • Genetic counseling services
    • Clinical physicists: some centers have these individuals on staff and they can assist in calculating actual radiation dose and risks associated with exposure in pregnancy

SYNOPSIS:

The radiation exposure in pregnancy from CT procedures varies depending on the number and spacing of adjacent imaging sections. It is very unusual for a patient to be exposed to sufficient radiation to cause any significant adverse events. Clinically documented intellectual disability requires at least 610 mGy and growth restriction and anomalies have been reported at levels greater than 50mGy.

KEY POINTS:

Fetal Radiation Dose and CT Exam Type

Dosage levels

  • Very low-dose exam: 0.1 mGy
  • Low- to moderate-dose exam: 0.1-10 mGy
  • Higher-dose exam: 10-50 mGy

Type of CT Exam 

  • Head or neck CT (very low-dose)
    • 0.001-0.01 mGy
  • Chest CT or CT pulmonary angiography (low- to moderate-dose)
    • 0.01-0.66 mGy
  •  Limited CT pelvimetry (low- to moderate-dose)
    • <1 mGy
  • Abdominal CT (higher-dose)
    • 1.3-35 mGy

Pulmonary Embolism

  • A CT evaluation of the chest results in a lower dose of fetal exposure to radiation compared with ventilation perfusion scanning
  • Radiation exposure from a spiral CT is comparable to conventional CT
  • The most commonly used contrast material is an iodinated media which carries a low risk of adverse effects
  • Contrast
    • Should be used only if absolutely required to obtain additional diagnostic information
    • Breastfeeding can be continued after the use of iodinated contrast material

Learn More – Primary Sources:

ACOG Committee Opinion 723: Guidelines for Diagnostic Imaging During Pregnancy and Lactation

Locate a Genetic Counselor or Genetics services:

Genetic Services Locator-ACMG

Genetic Services Locator-NSGC

Genetic Services Locator-CAGC