Iodine 150 mg treatment

[Pia Ruohotie]

Hello!

We are looking information about resuming breastfeeding after pre-operative treatment of potassium iodine 150 mg x 1 for 14 days before thyroid operation. Permission to post.

The parent is breastfeeding 4 month old baby and has medication resistant hyperthyroidism. The parent wishes to resume breastfeeding after iodine treatment and operation but there are no information available how long they should wait after iodine treatment. The Teratologinen Information Center of Finland could not give information about how long to wait. The parent is going to pump breast milk and discard the milk as long as needed before trying to resume breastfeeding.

I checked Infant Risk app and did not find information either.

Your sincerely,
Pia Ruohotie
RN, IBCLC from Helsinki, Finland

[nicholec]

Hi Pia,

Will this mother be getting radioactive iodine during her operation or are they removing the thyroid entirely?

[Pia Ruohotie]

They are not using radioactive isotope at all. They are using potassium iodide to treat the thyroid 14 days before operation where the whole thyroid is removed. The hyperthyroidism didn’t react any medication which was tried before.

we have not found information how long the parent needs to wait after potassium iodide before resuming the breastfeeding after operation.

[kaytlin]

Hi Pia!

I wanted to address your inquiry, though the available data on this topic is limited.

The primary concern with high iodine intake through breast milk is the Wolff-Chaikoff effect in the infant, which is a temporary suppression of thyroid hormone production following excessive iodine exposure. This effect is particularly concerning for infants, as their neonatal thyroid glands are thought to be more susceptible to iodine toxicity. Unlike adults, it has been believed that infants might not fully recover from iodine-induced hypothyroidism, potentially leading to permanent conditions.

For further insight, I recommend reviewing a recent article on iodine and lactation authored by Anderssen. It includes a detailed "Health Consequences of Iodine Excess" section that could be highly informative.

The most relevant study we have is from Hamada in 2017, which investigated 26 breastfeeding mothers consuming 10-100 mg/day of potassium iodide, with a median intake of 50 mg/day, and monitored their infants' thyroid functions. Remarkably, only one infant displayed subclinical hypothyroidism, which resolved within two months.

Considering your patient's dose is notably higher, albeit for two weeks, I advise proceeding cautiously. Since a four-month-old infant consumes a significant amount of breastmilk and their metabolic systems are fairly developed, I advise suspending breastfeeding for at least 3-4 weeks following the final 150mg dose. After this period, and with approval from a pediatrician, resume partial breastfeeding (50%) for an additional month. During this time, keep an eye out for any symptoms of hypothyroidism in the infant, such as reduced activity, increased sleepiness, feeding challenges, or constipation. I would only recommend this regimen with the supervision of the pediatric team in a mother able to closely monitor the infant. Otherwise, a breastfeeding hold time might be 2 months (still recommending infant symptom monitoring).

If the pediatrician agrees and is willing to monitor the infant's TSH levels, attempting a more aggressive breastfeeding approach might be possible. Please ensure that any decisions are made in close consultation with healthcare professionals to prioritize the well-being of both mother and child.

I hope this helps,
Dr. Krutsch

Andersson M, Braegger CP. The Role of Iodine for Thyroid Function in Lactating Women and Infants. Endocr Rev. 2022;43(3):469-506. doi:10.1210/endrev/bnab029

Hamada K, Mizokami T, Maruta T, et al. Effects of Inorganic Iodine Therapy Administered to Lactating Mothers With Graves Disease on Infant Thyroid Function. J Endocr Soc. 2017;1(10):1293-1300. Published 2017 Sep 19. doi:10.1210/js.2017-00297

[kaytlin]

Hi Pia - I reached out to a team in the EU that may be able to quantify the amount of iodine in this patient's milk to help guide future similar cases. Would your patient want to work with their team to provide milk samples and health information? If so, I can start a discussion with the EU team.

[Pia Ruohotie]

Dear Dr. Krutsch!

I am very grateful about the information. I will share it with the parent and I will also ask they if they are willing to give a sample.

Gratefully,
Pia