Post-hemithyroidectomy Pregnancy Thyroid Function Surveillance - Frequency, Adherence and Guideline Impact

Abstract Purpose: Post-hemithyroidectomy women are at increased risk for gestational subclinical hypothyroidism. Therefore, the American Thyroid Association (ATA) recommends increased thyroid function surveillance for this subgroup of pregnant women. The Purpose of this study was to evaluate the frequency of thyroid function surveillance during pregnancy in post-hemithyroidectomy women, and to evaluate the adherence to the 2017 ATA guidelines and its possible impact since being published, on thyroid function surveillance rates.Materials and Methods: A retrospective study including all pregnancies conceived by post-hemithyroidectomy women operated at Kaplan Medical Center between the years 1997-2020. The study cohort was subdivided by pregnancy date prior to 2018 and 2018 and onwards to evaluate the impact of the 2017 ATA guidelines. Adherence to the guidelines was defined as at least one TSH test in each trimester. Results: After exclusions, a total of 120 pregnancies conceived by 66 women who underwent hemithyroidectomy surgeries were included in this study. Overall, serum TSH examinations were performed during the first, second and third pregnancy trimesters in 86.6%, 40% and 16.6% of pregnancies (P<0.005), respectively. The examination rate since 2018 was 88%, 40% and 8% for first, second and third trimester, respectively (P<0.005). No significant differences were found in serum TSH examination rates between pregnancies prior to and following the beginning of 2018 (P=.533). Conclusions: Adherence to the latest ATA guidelines is low and its publication in 2017 did not increase the thyroid function surveillance rate in post-hemithyroidectomy women. Better patient education regarding the risks of gestational hypothyroidism following hemithyroidectomy and improved communications between treating surgeons, obstetricians, and endocrinologists may improve these rates.