Re: PREGNANCY & I-131 HYPERTHYROID RX

[jtowson@nucmed.rpa.cs.nsw.gov.au (Jocelyn Towson)]

The ICRP 52 statement about allowing 6 months for I-131 decay/elimination
before attempting to become pregnant is comfortably conservative, given the
8 day half life.   I believe it takes some months after iodine therapy for
euthyroid status to be achieved and perhaps endocrine factors are more
significant than minute traces of radiation eg ,Casara et al, in "Pregnancy
after high therapeutic doses of iodine-131 in differentiated thyroid
cancer: potential risks and recommendations", Eur J Nuc Med (1993)
20:192-194, mention possible adverse effect on pregancy outcome of mild
hyperthyroidism from replacement thyroxine.

Jocelyn Towson
Royal Prince Alfred Hospital
Sydney

jtowson@nucmed.rpa.cs.nsw.gov.au