ORIGINAL RESEARCH article
Front. Nutr.
Sec. Nutritional Epidemiology
Stage-Specific Variations in Urinary and Salt Iodine among Pregnant Women in Beijing
Zhilin Wu
Yubin Zhang
Chao He
Wenzeng Zhang
Beijing Shunyi District Center for Disease Control and Prevention, Beijing, China
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
Abstract
Background: Iodine is essential for fetal neural development and thyroid function in pregnant women. Although China has a policy of iodizing salt, salt intake alone may be insufficient to fulfill the iodine needs of pregnant women, particularly in early gestation. Purpose: To evaluate trimester-specific and annual fluctuations in urine and salt iodine levels among pregnant women in Beijing from 2021 to 2024. Methods: Iodine data from 400 women were analyzed using descriptive statistics, ANOVA and MEM. Results: The median urinary iodine decreased from 151.3 µg/L in 2022 to 122.9 µg/L in 2024, falling outside the WHO recommended threshold of 150 µg/L. ANOVA indicated a substantially reduced urine iodine level in the first trimester compared to subsequent trimesters (F = 4.72, P = 0.011). MEM showed reduced levels in the first trimester (β=–0.34, P= 0.01), whereas salt iodine shown no variations across trimesters (β= 0.45, P= 0.80). The iodine content in salt remained consistent (19–22 mg/kg), however urine iodine decreased by 17–24% over time. Conclusions: Urinary iodine levels among Beijing pregnant women have declined significantly, particularly in early pregnancy. Iodized salt alone is insufficient to meet their needs, therefore enhanced iodine supplementation and early monitoring are crucial to ensuring sufficient iodine intake for embryonic development.
Summary
Keywords
Gestational stages, iodine deficiency, Pregnant Women, Salt iodine, Urinary iodine
Received
20 October 2025
Accepted
17 February 2026
Copyright
© 2026 Wu, Zhang, He and Zhang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Wenzeng Zhang
Disclaimer
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.