Last Revised: October 10, 2025
As an pregnant worker, you have the option to declare your pregnancy for radiation safety purposes. Declaring allows us to monitor radiation dose to your baby over the entire pregnancy. The radiation dose limit during the pregnancy is 500 mrem (5 mSv), or 10% of the annual occupational limit. It can be a confidential process – we communicate directly with you and are not required to share any information with your supervisor, OccMed, etc. in most cases. Any necessary changes to your work practices to ensure your dose remains within the limits will be discussed with your supervisor, if required. The written declaration can be submitted at any point during the pregnancy, and can also be rescinded at any point should you choose to do so. This is a completely voluntary process, so you have the right to forgo the declaration.
Any occupationally exposed pregnant worker can receive counseling and declare their pregnancy if they choose to do so. This includes workers at Penn, Penn Medicine, CHOP, the Wistar Institute, and satellite locations. Radiation Safety will provide information on dose reduction methods.
Below are some resources and additional information.
If you have any questions or concerns at any point pre-conception or post-conception, please feel free to reach out to our staff.
What do I need to know as a pregnant worker?
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The declaration process is completely voluntary and can remain confidential, if requested, but must be in writing.
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Your dose limit during your pregnancy is 500 mrem (5 mSv) if your pregnancy is declared in writing. For reference, your occupational dose limit is 5,000 mrem (50 mSv) if you do not declare or are not pregnant.
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How do I know what dose I have received in the past? Your dosimeter results are accessible at any time. Please see the instructions on how to access your dosimeter results here.
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Please let us know if you are or will be employed anywhere besides Penn or CHOP during your pregnancy.
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If your dose is not likely to exceed 100 mrem (1 mSv) during your pregnancy, an additional fetal dosimeter is not required. This is determined based on your previous occupational dose history and job duties. Typically, your existing dosimeter is an appropriate method for monitoring your baby’s exposure. An additional fetal dosimeter is often unnecessary.
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If a fetal dosimeter is required, the dosimeter will be exchanged on a monthly basis.
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NRC Regulatory Guide 8.13, “Instruction Concerning Prenatal Radiation Exposure”
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Instadose website (for those with a USB dosimeter) - to read your USB device
Supplemental Information
- NRC Regulatory Guide 8.36, “Radiation Dose to the Embryo/Fetus”
- Health Physics Society Ask the Experts: Pregnancy and Radiation Questions
- EHRS General Reproductive Health Information (not Radiation specific)
- MotherToBaby podcast Ep. 76: Radiation and Its Effects on Pregnancy
- MotherToBaby – workers and x-ray
- MotherToBaby – x-rays
- Diagnostic Radiation Exposure During Pregnancy
- The Penn Women’s Center
- IAEA Radiation protection of pregnant women in radiology
- Department of Labor Employment Protections for Workers Who Are Pregnant or Nursing by State
- Pregnant Workers Fairness Act (PWFA)
- Download a list of Penn Medicine Lactation Spaces, including off-campus locations.
- The Penn Women’s Center
- Penn Lactation Policy
- Drugs and Lactation Database (LactMed®)
- If you are currently breastfeeding or plan to begin breastfeeding in the near future and need to receive a scan or therapy involving a radiopharmaceutical (e.g., FDG PET/CT scan, MUGA scan, radio-thyroid therapy), inform the technologist, nurse or doctor prior to your scan.