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Hyperthyroidism in Pregnancy

Last Updated: · Doctors


I received your email address through and have a case I would like help with from your group of thyroid experts. A 29 yo G5P1A3( none spontaneous) referred to me 3/06/03 at 12 wks gestation for hyperthyroidism.

HX: Admitted for hyperemesis 2/26-3/3. Had a normal 8 wk u/s. Normal fetal heart rate. Asx except for vomiting which had improved since discharge, although still present. Also weight loss improving. Had lost 25 lbs over 8 wks before admission. At time of d/c wieght was 116(3/3). At time of visit 3/6 regained to123lbs. No tremor/palp//heat intoler Meds: Zofran. FHX neg for thyroid dz.
PE: wt 123 94/34 P:100.No thyroid enlarg, no tremor no signs of Graves or hyperthyr.
DATA: 2/26 TSH 0.02, ft4 2(.59-1.17) T3 363(85-205) HCG: 116,9813/6/03: TSH 0.02 fT4 1.48 (.58-1.64) T4:18 T3: 404 T3RU:24(24-39)fT4 eq dial (Nichols) 2.5 (.8-2.7) BUT 1st trimester (.7-2) 2nd trimester (.5-1.6)fT3 530 (pregnancy ref: 200-380) T3:328 (Nichols) AntiTPO/TG Abs neg.
F/U: 3/18/03: 14 wks gest , still vomiting but better. No other sx. Wt 120 1/2 (down 2 lbs in 2 wks). I am ordering a repeat fT3 and fT4(eq dial) , TSAb and HCG. Would you treat her with AT Drugs or beta blocker?Any further dx tests or treatment recs?

Lisa Wisniewski, MD


This case looks like the typical patient with "GTT" (gestational transientthyrotoxicosis), without manifestations of thyrotoxicosis, except for those associated to emesis (such as weight loss, etc) and with progressive and spopntaneous improvement. Typical is also the high hCG value, above 100,000. I would certainly not give ATD nor beta-blocking agents, in view of the spontaneous amelioration.In all the similar cases we have followed (over 50 now), symptoms disappeared before mid-gestation and the remainder of the pregnancy was uneventful, with delivery of normal babies.A last word: it may be useful to carry out a thyroid ultrasonography (nowor later) or to see the patient again once after the delivery. This is intended to diagnose those rare instances in which thyroidal overstimulation, due to the high and sustaioned hCG levels, is associated with an underlying thyroid abnormality (such as micronodular autonomous goiter, etc).

Dr Daniel Glinoer


Dear Dr. Glinoer,

Thank you very much for your response re: my patient. I twas very helpful.The patient was seen in early April and is clinically doing fairly well. She was 16-17 wks gestation with weight stable, still vomiting though less. But biochemically ft4 and ft3 have increased. FreeT3: 595 (200-380 pregn) Up from 530 at 13 wks. FT4: 3.2 (.5-1.6 2nd trimester). Up from 2.5 at 13 weeks. do you still feel it is best to hold off on antithyroid drugs? I will re-draw these as she is further in to the 2nd trimester.

Best regards,

Lisa Wisniewski, MD