When can I resume breastfeeding after I-123?

[trolley]

Received a dose of .200 microcuries of I-123 for a thyroid scan. Hospital said 72 hours out of an abundance of caution given the half life of 13 hours. I've been trying to research to understand how much of this gets into the breast milk and the risk to my baby of nursing before the 72 hour mark. At what point is the risk decreased?

If I understand half life correctly, a 13 hour half life means that

• 13 hrs after dose -- 50% concentration in my body
• 26 hours after --> 25% concentration
• 39 hrs after --> 12.5%
• 52 hrs after --> 6.25%

At what point is it "safer" to nurse my baby a little? That is, to still give mainly bottles but to put the baby on the breast once for 5-10 min before the 72 hour mark?

[nicholec]

Pumping and dumping for 3 days is the recommendation to avoid thyroid dysfunction in your infant. I recommend waiting a full 72 hours from the time that the contrast was administered before you resume breastfeeding.

[kaytlin]

It's always a good idea to verify the recommendations you get about your meds--radioactive iodine is one of the drugs we watch for. Iodine gets actively transported into the breast, and it is more risky than most meds (though it depends on the isotope!)

[trolley]

Thanks, all! Really appreciate it