Endocrine Abstracts

Introduction: Overt thyroid dysfunction in pregnancy without an early diagnosis and treatment may lead to an increased risk of adverse maternal and fetal outcomes. In this study, our goal was to assess the results of the development of a laboratory alerting system for the diagnosis of thyroid dysfunction in the first trimester of pregnancy.

Material and methods: Observational retrospective study evaluating clinical and biochemical data from pregnant women with overt thyroid dysfunction diagnosed in the first trimester of pregnancy through a laboratory alerting system between October 2020 and August 2021. Overt thyroid dysfunction was defined by overt hypothyroidism (TSH < 4 mcU/ml and low FT4) or overt hyperthyroidism (TSH < 0.1 mcU/ml and high FT4/FT3) in the first trimester of pregnancy. Laboratory alerts were received weekly via e-mail notification and assessed by an Endocrinologist.

Results: A total of 60 laboratory alerts were received. 12 of them did not fulfill the aforementioned criteria and were not considered. Thus, the remaining 48 laboratory alerts from women in the first trimester were evaluated (30.8 ± 7.1 years old, 20.8% presented family history of thyroid disease and 14.5% presented personal history of thyroid disease (6.2% hypothyroidism, 8.3% hyperthyroidism). Considering the 13 laboratory alerts related with overt hypothyroidism, 5 patients presented increased levels of thyroperoxidase antibodies (38.4%), median TSH 7.3 (4.38-617; normal value 0.4-4 μUI/ml), median FT4 10.4 pmol/l (1.98-10.94; normal value: 11-22 pmol/L). 7 women (53.8%) started levothyroxine (median TSH 13.4 μUI/ml), 1 patient was not contacted, and 5 patients presented analytical interferences (normal TSH and slightly decreased FT4) and were not treated. With regard to the 35 laboratory alerts due to overt hyperthyroidism, 3 patients (8.5%) had personal history of transient hyperthyroidism of early pregnancy; 17 (48.6%) presented nausea/vomiting, 1 (2.9%) twin pregnancy and 1 (2.9%) ectopic pregnancy. Positive autoimmunity (TSI) was detected in 5 patients (14-3%), median FT4 22.6 pmol/l (ranging from 22.04 to 55.79), median FT3 7.73 pmol/l (6.88-30.8; normal value 3.1-6.8). 10 patients (28.5%) started treatment with antithyroid drugs, whereas in the rest, the transitory suspension of the iodine supplement was enough for the normalization of biochemical parameters.

Conclsions: A laboratory alerting system for the diagnosis of thyroid dysfunction during pregnancy permitted an early diagnosis and treatment of this pathology in 28.8 % of the received laboratory alerts.