I would appreciate if I can get your valuable suggestions on a case of autoimmune thyroid disease in pregnancy that I am dealing with.The lady is 25 years old married Indian Muslim. Her husband is her first cousin as well. She is primigravida. Her first presentation was at 8 weeks of gestation with the following abnormal TFT results-
24.05.2011 (at 6 weeks gestation)-TSH 0.15 microIU/ml (0.35-5.5)
27.05.2011 TSH- 0.06 µIU/ml (0.35-5.5), FT4- 2.07 ng/dl (0.8-1.8), FT3- 5.78 pg/ml (1.4-4.4)
05.06.2011- TSH 0.078 (0.27-4.2).
She attended my clinic on 11.06.2011 . She had US done on 08.06.2011 which showed single live fetus 8 weeks & 3 days size.On enquiry & physical examination she had no goitre and no other signs & symptoms suggestive of hyperthyroidism.There was no history of thyroid disorder in her or her husband's family. She gave history of persistent nausea and a few episodes of vomiting from the beginning of her pregnancy, which was gradually settling down. I made a diagnosis of Hyperemesis gravidarum & gestational thyrotoxicosis and informed her that her TFT were likely to go back to normal over the next 4 to 8 weeks time and she did not require any treatment.
On 08.07.2011 she visited another endocrinologist. He did the following tests on her-
11.07.2011 TSH- 0.046 µIU/m l (0.27-4.2) , FT4- 11.87 pmol/L(12-22),AntiTPO antibody 85.95 IU/ml (<34)
Ultrasound thyroids normal morphology with no increased blood flow on doppler..On full examination he also did not find any abnormal features suggestive of hyperthyroidism and agreed with my diagnosis of gestational thyrotoxicosis.
I examined her on 22.08.2011 with the following TFT results-
19.08.2011; TSH 7.41 µIU/ml (0.27-4.2),FT4 10.08 pmol/L (12-22),AntiTPO antibody 90.51 IU/ml (<34).
23.08.2011 TSH 12.919 microIU/ml (0.35-5.5),FT4 0.85 ng/dl (0.89-1.76), AntiTPO antibody 84.4 U/ml (<60).
I have started her on LT4 50 micrograms per day and plan to review her at 4 weeks with repeat TSH & FT4.I suspect she has Graves' disease with changing nature of TSH receptor antibody.
I plan to measure her TSH receptor antibody at 6 weeks postpartum. Praveen Shankar, Ranchi, India
I believe your patient started with the normal suppression of TSH caused by hCG in early pregnancy, and minimal increase in thyroid hormone levels. In the second trimester as hCG subsided, her endogenous thyroid function driven by TSH took over. She certainly has autoimmune thyroid disease, and seems intrinsically hypothyroid.. Whether she has Graves disease and blocking antibodies is unknown, and perhaps unlikely.. Most likely she has Hashimoto's thyroiditis, and is now mildly hypothyroid, needing supplementation, as you have done. She needs close follow to get her TSH quickly and consistently into the 2.5-3 range. Best regards, L De Groot, MD