Quick answer: You can usually keep breastfeeding after a CT scan with iodine contrast or an MRI with gadolinium contrast. The American College of Radiology (ACR) and the American College of Obstetricians and Gynecologists (ACOG) say there’s no need to stop, because only a tiny amount reaches your milk and even less is absorbed by your baby. If you’d still feel better waiting, you can choose to pause for 12 to 24 hours, but it’s optional. Nuclear medicine and PET scans are different: some radioactive tracers do require a pause, so always ask.
How much contrast gets into breast milk?
- Iodine contrast (CT): Less than 1% of the dose passes into breast milk, and less than 1% of that is absorbed from the baby’s gut. In total, the baby gets less than 0.01% of the mother’s dose.
- Gadolinium contrast (MRI): An even smaller fraction reaches breast milk, and very little is absorbed by the baby.
These amounts are far below the doses sometimes given directly to babies for their own scans.
What the guidelines say
- ACR: Available data suggest it’s safe for both mother and baby to continue breastfeeding after iodine or gadolinium contrast.
- ACOG: Breastfeeding should not be interrupted after iodine or gadolinium contrast.
- If you’re worried: ACR says a mother may choose to stop breastfeeding for 12–24 hours and pump and discard her milk during that time. There’s no benefit to waiting longer than 24 hours. It’s your choice, not a medical requirement.
If you choose to pause
- Pump before the scan and store enough milk for the next 12–24 hours, if you can.
- After the scan, pump and discard milk during the time you’ve chosen, so your supply stays up and you stay comfortable.
- Resume breastfeeding normally after that.
Tell the imaging team you’re breastfeeding. Many centers have a private space where you can pump.
Nuclear medicine and PET are different
Nuclear medicine and PET scans use radioactive tracers, not contrast dye. Some tracers pass into breast milk, and the baby can also be exposed by being held close to the mother for a while after the scan.
- Many common tracers need only a short pause from breastfeeding, sometimes with limits on close contact for a few hours.
- Some tracers require a longer pause.
- Radioactive iodine (I-131) treatment usually means stopping breastfeeding for that child completely.
The exact advice depends on the tracer and the dose. Your nuclear medicine team will give you specific instructions. Tell them you’re breastfeeding before the scan is scheduled, so they can plan it with you.
From the scanner room
[TU EXPERIENCIA: tu especialidad. Qué indicáis en tu servicio a una madre lactante tras Tc-99m, F-18 FDG o I-131 (si quieres, añade una tabla orientativa citando la guía que seguáis: NRC, ICRP o SNMMI); cómo se gestiona el contacto cercano con el bebé; y la confusión frecuente entre contraste y radiofármaco.]
Practical tips
- Mention breastfeeding when you book, especially for nuclear medicine.
- Ask what type of agent you’ll receive: iodine contrast, gadolinium contrast or a radioactive tracer.
- Bring your pump or ask whether the center has one.
- Stay hydrated and keep to your usual feeding or pumping schedule as much as possible.
FAQ
Do I need to pump and dump after a CT scan with contrast?
No. Guidelines say you can keep breastfeeding. Pausing for 12–24 hours is optional if it makes you feel more comfortable.
Is it safe to breastfeed after an MRI with gadolinium?
Yes. Very little gadolinium reaches breast milk, and guidelines say breastfeeding can continue.
Can I breastfeed after a CT scan without contrast?
Yes. X-rays and CT don’t leave any radiation in your body or milk.
Can I breastfeed after a PET scan?
It depends on the tracer. Many PET scans need a short pause and some limits on close contact. Your nuclear medicine team will give you exact instructions.
Does contrast change the taste of breast milk?
Some mothers report that the baby seems to notice a slight difference, but there’s no evidence of harm.
This article is for general information only and is not medical advice. Tell your imaging team you’re breastfeeding and follow the instructions they give you, especially for nuclear medicine.
Sources
- ACR Manual on Contrast Media: Administration of contrast media to women who are breastfeeding.
- ACOG Committee Opinion No. 723: Guidelines for Diagnostic Imaging During Pregnancy and Lactation.
- UC San Diego Radiology. Breastfeeding policy for iodinated and gadolinium contrast (based on ACR guidance).
- U.S. NRC. Guidance on release of patients and breastfeeding after radiopharmaceuticals (NUREG-1556).
- SNMMI. Patient information on nuclear medicine and breastfeeding.