6621 Iodine Nutritional Status in Different Trimesters of Pregnancy: A Prospective Observational Study in Taiwan

Abstract Disclosure: L. Pan: None. C. Yeh: None. C. Yang: None. C. Hwu: None. H. Chen: None. F. Wang: None. C. Huang: None. Pregnant women are susceptible to iodine deficiency. Iodine nutritional studies in pregnant women were mostly cross sectional evaluations of iodine status. This prospective observational study was designed to longitudinally follow the iodine status of pregnant women in different trimesters of pregnancy and to assess the clinical parameters and dietary influences on iodine status. A total of 209 pregnant women in their first trimester were enrolled in Taipei Veterans General Hospital, Taiwan from March 2019 to March 2023. Subjects provided a spot urine sample and completed a food frequency questionnaire at each trimester. Urinary iodine concentration (UIC) was measured by inductively coupled plasma mass spectrometry. The median UIC for the first, second and third trimester was 156.3 μg/L (Interquartile range [IQR]: 100.7-241.1), 146.2 μg/L (84.6-224.4), and 169.9 μg/L (94.4-283.5), respectively. Mild iodine deficiency was observed in the second trimester despite adequate iodine status in the first and third trimesters. Compared to the first trimester, intake of seaweed (p = 0.004, p < 0.001, respectively), fish (p < 0.001, p < 0.001, respectively), and prenatal multivitamins (p < 0.001, p < 0.001, respectively) increased in the second and third trimesters. A gradual increment in dairy product intake was also noted between each trimesters through pregnancy (p < 0.001, p = 0.004, respectively). Multivariate analysis indicated a positive association between multiparity and increased UIC in the second trimesters (multiparity vs. uniparity; adjusted odds ratio [OR]: 2.273, 95% confidence interval [CI]: 1.202-4.310). Additionally, increased prenatal multivitamin intake elevated the odds of adequate UIC in the third trimester (≥ 3 days/week vs. ≤ 1 day/week; adjusted OR: 2.890, 95% CI: 1.351-6.173). This study revealed the longitudinal changes in iodine status during pregnancy and suggested that women who regularly took prenatal multivitamins and were multiparous were more likely to have adequate iodine nutrition. Presentation: 6/2/2024