SPONTANEOUS HASHIMOTO’S THYROIDITIS REMISSION IN TWO CONSECUTIVE PREGNANCIES

Abstract

INTRODUCTION
Hashimoto ’s thyroiditis (HT), a type of autoimmune thyroid disorder, is the most common cause of hypothyroidism.
The course of HT is altered during pregnancy with majority of cases requiring an increment in levothyroxine doses as
high as 20-40% to achieve euthyroidism. Spontaneous remission of HT during pregnancy is extremely rare.

CASE
We describe a 37-year-old female who was diagnosed with Hashimoto’s thyroiditis initially presenting with neck
swelling and symptoms of hypothyroidism seven months after her first pregnancy. Her thyroid function test showed
overt hypothyroidism (TSH 83.9 IU/ml, FT4 3.9 pmol/L) with positive anti-thyroid peroxidase antibody (TPO Ab) at
196 IU/ml (>34), and thyroid stimulating immunoglobulin of less than 0.1 IU/L. She was started on levothyroxine 100
mcg daily. Patient had a miscarriage during her second pregnancy. On her third pregnancy, she developed hyperthyroidism at 10 weeks of gestation, requiring gradual reduction of her thyroxine and eventual discontinuation at
2 months postpartum. Thyroxine was resumed 6 months postpartum due to overt hypothyroidism. A similar
pattern was observed in her fourth pregnancy wherein she developed hyperthyroidism at 13 weeks also requiring
gradual reduction and later discontinuation of thyroxine at 35 weeks of gestation. Anti-TPO Ab at 35 weeks of gestation
was still elevated at 158.2 IU/ml. Her pregnancy was uneventful and she delivered a healthy baby. She remains
in remission three months postpartum.

CONCLUSION
Spontaneous remission of HT can occur during pregnancy, usually beyond the second trimester. However, recurrence
of HT has been observed during the postpartum period. Thyroid autoantibodies may play a role in these changes.
Close monitoring of thyroid function is essential.