In helping this mother facing radiation therapy, I had a hard time
grappling with the rationale behind weaning well *before* treatment for
this particular isotope (particularly since temporary weaning is
sufficient for a lot of radiological treatments). So I'm copying a good
explanation that Thomas Hale had posted quite a while ago, since it
might be useful to others.
There's some disagreement, also in the archives, about the theoretical
risks, and whether continuing to lactate and pumping and dumping
frequently is an option. (In my particular case, the mother would not
be willing to pump-and-sacrifice the milk for the two months necessary
to clear the system anyway.)
Here's Hale's post:
> Date: Mon, 24 Aug 1998 16:05:58 -0400
> Reply-To: Lactation Information and Discussion <[log in to unmask]>
> Sender: Lactation Information and Discussion <[log in to unmask]>
> From: "Dr. Tom Hale" <[log in to unmask]>
> Subject: I-131
> Content-Type: text/plain
>
> To: My Colleagues Re: Iodine-131 There have been a number of comments regarding the use of Iodine-131 in a breastfeeding mother that have been in error and I would like to correct some misunderstandings re the pharmacology of this interesting ion. Iodine-131 is specifically sequestered and concentrated in the thyroid. The thyroid gland has a membrane-specific pumping system that selectively pumps iodine from the maternal plasma compartment into the patients thyroid...and produces about at 40-50 fold concentration gradient in the thyroid. This is why when you administer I-131, that about 45% of the dose 'will concentrate in the thyroid', attaining high levels, hence ablating or destroying thyroid tissue. Another major problem, is that about 40% of the dose will transfer into the lactating breast alveoli(because it too has a pumping system), so that the breast tissue concentrates vast quantities as well. Hence it has been theorized that it might be dangerous for breastfeedin
g mother to use radioiodine. After the initial dose, most of it will stay in the thyroid gland until it is decayed away at the rate of one-half in 8 days (about 40 days for 97% decay). Some will distribute to the body, but only minimal amounts. It is my contention, that if a mom needs a thyroid ablation, then she should discontinue breastfeeding for long enough for her breasts to discontinue making milk, hence reducing the amount selectively transferred into this tissue (thereby no "theoretical" risks to the breasts such as breast cancer). Cabergoline would probably be a suitable product to inhibit lactation. I know from personal experience, that the thyroid emits huge amounts of radiation for some time, which is the reason that the radiologist suggests she not hold her child. I once placed a gamma counter to the thyroid of such a patient, and it went off the meter (I regretted having done this as the patient was quit concerned). A thin lead blanket wrapped around the thyroid
would stop this. So, things to remember are: I-131 concentrates in thyroid tissue and the lactating breast tissue. It is slow to decay with an 8 day half-life. If the infant is breastfed, it could produce severe thyroid problems, including increasing the risk of thyroid carcinoma in later life. Regards Tom Hale, Ph.D.
>
> Back to: Top of message | Previous page | Main LACTNET page
***********************************************
To temporarily stop your subscription: set lactnet nomail
To start it again: set lactnet mail (or digest)
To unsubscribe: unsubscribe lactnet
All commands go to [log in to unmask]
The LACTNET mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software together with L-Soft's LSMTP(R)
mailer for lightning fast mail delivery. For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html
|
