Effects of iodine supplementation on thyroid function parameter: Systematic review and meta-analysis

source extracted confidence: high 2026-04-09
#pregnancy #female #humans #iodine #thyroid-gland

Effects of iodine supplementation on thyroid function parameter: Systematic review and meta-analysis

Candido et al., 2023 | J Trace Elem Med Biol | Meta Analysis

Citation

Candido Aline Carare, Azevedo Francilene Maria, ... Castro Franceschini Sylvia do Carmo. Effects of iodine supplementation on thyroid function parameter: Systematic review and meta-analysis. J Trace Elem Med Biol. 2023-Dec;80:127275. doi:10.1016/j.jtemb.2023.127275

Abstract

BACKGROUND: Supplementation is an alternative with potential benefits for the prevention of iodine deficiency in pregnancy. OBJECTIVE: To evaluate the effects of iodine supplementation on maternal thyroid hormone concentrations and iodine status during and/or before pregnancy. METHODS: The review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). The search was conducted in the databases: Cochrane, Embase, Pubmed/MEDLINE and Scopus. Studies involving pregnant women of all trimesters who received oral iodine supplementation were included. Study selection was performed in the Rayyan program. Risk of bias was assessed by the Joanna Briggs Institute tool. Meta-analysis was performed in R software version 4.0.4. RESULTS: Eleven articles with low and moderate risk of bias were included. According to the results of the meta-analysis, supplementation of 200 μg/day of iodine was able to change urinary iodine concentration during pregnancy, thus contributing to adequate intake. When evaluating the period when the intervention started, the best time to start supplementation was prior to pregnancy or in early pregnancy. CONCLUSION: Daily iodine supplementation had satisfactory effects on iodine status and maternal thyroid hormone concentrations. Although supplementation with 200 µg showed positive effects on iodine status in pregnancy, some studies showed no effect. Prospero Registration: CRD42021249307 (https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=249307).

Key Findings

Eleven articles with low and moderate risk of bias were included. According to the results of the meta-analysis, supplementation of 200 μg/day of iodine was able to change urinary iodine concentration during pregnancy, thus contributing to adequate intake. When evaluating the period when the intervention started, the best time to start supplementation was prior to pregnancy or in early pregnancy.

Outcomes Measured

  • Requires manual extraction

Population

Field Value
Population See abstract
Sample Size See abstract
Age Range See abstract
Condition deficiency

MeSH Terms

  • Pregnancy
  • Female
  • Humans
  • Iodine
  • Thyroid Gland
  • Dietary Supplements
  • Thyroid Hormones
  • Pregnant People

Evidence Classification

  • Level: Meta Analysis
  • Publication Types: Meta-Analysis, Systematic Review, Journal Article
  • Vertical: iodine-thyroid

Provenance

Source extracted via PubMed E-utilities API on 2026-04-09