Consequences of inadvertent radioiodine treatment of Graves' disease and thyroid cancer in undiagnosed pregnancy. Can we rely on routine pregnancy testing?
BACKGROUND
Radioiodine and most cytostatic treatments are contraindicated in pregnancy. Still, inadvertent therapy does occur. Radioiodine was given to two pregnant women with Graves' disease and thyroid cancer respectively, both in their 20th gestational week. Routine pregnancy tests based on urinary beta-hCG had failed to indicate pregnancy in both cases.


METHODS
Estimation of doses to the foetuses and foetal thyroids. Scrutiny of pregnancy testing.


CONCLUSIONS
Doses to foetal thyroids were ablative (250-600 Gy). Total foetal dose in the Graves' patient was 100 mGy and compatible with survival, whereas a foetal dose of approximately 700 mGy together with induced hypothyroidism was fatal for the foetus of the cancer patient. Routine pregnancy tests may fail early and late in pregnancy. The possibility of pregnancy should be considered in all fertile women before therapy with radionuclides or cytostatic regimens, and a clinical investigation undertaken on wide indications with determination of serum beta-hCG, preferably together with an ultrasound examination.
Berg
Gertrud
G
Department of Oncology, Sahlgrenska University Hospital, Sahlgrenska Academy, Göteborg, Sweden. gertrud.berg@oncology.gu.se
Jacobsson
Lars
L
Nyström
Ernst
E
Gleisner
Katarina Sjögreen
KS
Tennvall
Jan
J
D000028:Abortion, Induced; D000328:Adult; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D005260:Female; D006111:Graves Disease / Q000532:radiotherapy*; D006801:Humans; D007457:Iodine Radioisotopes / Q000008:administration & dosage / Q000009:adverse effects*; D018743:Perinatal Care; D011247:Pregnancy; D011252:Pregnancy Complications, Neoplastic / Q000532:radiotherapy*; D011256:Pregnancy Outcome; D013961:Thyroid Gland / Q000528:radiation effects*; D013964:Thyroid Neoplasms / Q000532:radiotherapy*
D018997:Chorionic Gonadotropin, beta Subunit, Human; D007457:Iodine Radioisotopes