CMECNE

Exposure to Ionizing Radiation During Pregnancy – What Now?

Learning Objectives and CME/Disclosure Information

This activity is intended for healthcare providers delivering care to women and their families.

After completing this activity, the participant should be better able to:

1. Discuss the risks to lactation from ionizing radiation
2. Discuss the fetal risk associated with radiation exposure of > 50 mGy

Estimated time to complete activity: 0.25 hours

Faculty:

Susan J. Gross, MD, FRCSC, FACOG, FACMG
President and CEO, The ObG Project

Disclosure of Conflicts of Interest

Postgraduate Institute for Medicine (PIM) requires faculty, planners, and others in control of educational content to disclose all their financial relationships with ineligible companies. All identified conflicts of interest (COI) are thoroughly vetted and mitigated according to PIM policy. PIM is committed to providing its learners with high quality accredited continuing education activities and related materials that promote improvements or quality in healthcare and not a specific proprietary business interest of an ineligible company.

The PIM planners and others have nothing to disclose. The OBG Project planners and others have nothing to disclose.

Faculty: Susan J. Gross, MD, receives consulting fees from Cradle Genomics, and has financial interest in The ObG Project, Inc.

Planners and Managers: The PIM planners and managers, Trace Hutchison, PharmD, Samantha Mattiucci, PharmD, CHCP, Judi Smelker-Mitchek, MBA, MSN, RN, and Jan Schultz, MSN, RN, CHCP have nothing to disclose.

Method of Participation and Request for Credit

Fees for participating and receiving CME credit for this activity are as posted on The ObG Project website. During the period from Dec 31 2017 through Dec 31 2021, participants must read the learning objectives and faculty disclosures and study the educational activity.

If you wish to receive acknowledgment for completing this activity, please complete the post-test and evaluation. Upon registering and successfully completing the post-test with a score of 100% and the activity evaluation, your certificate will be made available immediately.

For Pharmacists: Upon successfully completing the post-test with a score of 100% and the activity evaluation form, transcript information will be sent to the NABP CPE Monitor Service within 4 weeks.

Joint Accreditation Statement

In support of improving patient care, this activity has been planned and implemented by the Postgraduate Institute for Medicine and The ObG Project. Postgraduate Institute for Medicine is jointly accredited by the Accreditation Council for Continuing Medical Education (ACCME), the Accreditation Council for Pharmacy Education (ACPE), and the American Nurses Credentialing Center (ANCC), to provide continuing education for the healthcare team.

Physician Continuing Medical Education

Postgraduate Institute for Medicine designates this enduring material for a maximum of 0.25 AMA PRA Category 1 Credit(s)™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Continuing Nursing Education

The maximum number of hours awarded for this Continuing Nursing Education activity is 0.2 contact hours.

Read Disclaimer & Fine Print

CLINICAL ACTIONS:

When considering the effects of ionizing radiation during pregnancy:

Do not recommend termination solely on the basis of exposure to ionizing radiation
Patients should be counseled and prenatal imaging performed for structural anomalies and growth restriction for exposure >50mGy
- Radiation exposure through radiography, CT scan or nuclear imaging is usually at a dose that is lower than the threshold exposure associated with risk to the fetus and should not be withheld if necessary
Ultrasound and MRI are not associated with fetal risk and are first line imaging modalities
- Use ‘prudently’ and when the results will provide medical benefit
Consult radiation physicist to calculate total dose, if multiple imaging studies were performed
- The Health Physics Society (HPS) maintains an open access website with information for professionals and patients (see ‘Learn More – Primary Sources’ below)
A 10-20 mGy fetal exposure may increase the background risk of leukemia by a factor of 1.5-2.0
There is no risk to lactation from external sources of ionizing radiation

Interim ACOG Update (October 2017) Regarding Exposure to MRI and Gadolinium in Pregnancy

Limit the use of gadolinium contrast with MRI
Only use gadolinium contrast if it ‘significantly improves diagnostic performance’ and will improve maternal and/or fetal outcomes
Breastfeeding should not be interrupted after use of gadolinium, consistent with ACR guidance
A recent retrospective cohort study by Ray et al. (JAMA, 2016) comparing gadolinium MRI (n = 397) at any time during pregnancy with no MRI (n = 1,418,451), demonstrated
- The risk of any rheumatological, inflammatory, or infiltrative skin condition in offspring was increased (adjusted hazard ratio (HR) 1.36; 95% CI, 1.09 to 1.69)
- Stillbirths and neonatal deaths (within 28 days of birth) were increased (adjusted relative risk 3.70; 95% CI, 1.55 to 8.85) for an adjusted risk difference of 47.5 per 1000 pregnancies (95% CI, 9.7 to 138.2)

SYNOPSIS:

X-ray procedures may be indicated during pregnancy or may occur inadvertently before the pregnancy is diagnosed. The risk to a fetus from ionizing radiation is dependent on the gestational age at the time of the exposure and the dose of radiation. Growth restriction, microcephaly and intellectual disability are the most common adverse effects from high dose radiation exposure. They have not been reported with radiation exposure less than 50 mGy. Actual fetal doses are dependent on gestational age, maternal body habitus and acquisition parameters.

KEY POINTS:

Fetal Dose for common radiologic exams

Chest X-ray, two views generally: 0.0005-0.01 mGy
Abdominal radiography: 0.1-3 mGy
IVP: 5-10 mGy
Double contrast barium enema: 1.0-20 mGy
Head or neck CT: 1.0-10 mGy
Chest CT or CT pulmonary angiography: 0.01-0.66 mGy
Abdominal CT: 1.3-35 mGy

‘All or None’ Effect

Before implantation (0 to 2 weeks after fertilization)
- Death of embryo or no consequence
- Estimated threshold: 50-100 mGy

Learn More – Primary Sources:

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

JAMA: Association Between MRI Exposure During Pregnancy and Fetal and Childhood Outcomes

HPS: Radiation & Reproduction

HPS: Pregnancy and Radiation Exposure – Patient FAQs

ACR Manual on Contrast Media

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Exposure to Ionizing Radiation During Pregnancy – What Now?