Endocrine Abstracts

Introduction: Urinary iodine concentration (UIC) can reflex recent changes in iodine status and serve as a sensitive marker of current iodine intake. The cut-off value of UIC was determined as the level lower than 100 μg/l. Adequate median urinary iodine for iodine intake in pregnancy is 150–249 μg/l. The aim of this study was to map the situation of iodine intake in pregnant women with pregestational and gestational diabetes and to explore relationship with thyroid function.

Methods: We have measured UIC in 252 pregnant women screened positive for pregestational or gestational diabetes in second trimester of pregnancy. Currently, serum levels of autoantibodies against thyroid peroxidase (TPOAb) and thyroglobulin (TgAb), TSH, and free thyroxine (FT₄) were determined.

Results: Median UIC was 90.90 μg/l (range 20–4725 μg/l). In 222/252 (88.1%) women UIC was lower than 150 μg/l (median 85.70 μg/l) and in 151/252 (59.9%) was lower than 100 μg/l. UIC in the range appropriate with mild iodine deficiency (50–149 μg/l) was measured in 195/252 (76.2%) women and 27 (10.7%) values were found in the range of moderate deficiency (20–49 μg/l). Any value of UIC was lower than 20 μg/l. In nine women were measured levels in the adequate range for pregnant women (150–249 μg/l). In 21 women (8.3%) was UIC higher than 249 μg/l (median 305.1 μg/l). In women with the UIC <150 μg/l was found significantly higher serum TSH in comparison to them with UIC ≥150 μg/l (1.866 mIU/l vs 2.079 mIU/l, P<0.001).

Conclusion: In total 88.1% of women screened positive for gestational or pregestational diabetes were iodine deficient in second trimester of pregnancy and had slight elevation of serum TSH as compared to them with sufficient iodine intake.

Disclosure: This work was supported by the Research Programme Prvouk 25 of Charles University in Prague.