ArticlePublic health nutrition2019
Variation of iodine status during pregnancy and its associations with thyroid function in women from Rio de Janeiro, Brazil.
Article in Public health nutrition, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 10 papers, 2 of them syntheses that pooled it.
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Who cites it
10 citing papers in PubMed, 2 syntheses or guidelines pooled it, 21 citations in OpenAlex.
- Risk Factors for Thyroid Function Test Abnormalities During Pregnancy: A Systematic Review of the Literature to Validate Current Risk Factors and Identify Novel Ones.Thyroid : official journal of the American Thyroid Association · 2025Pooled it
- Prevalence of Excessive Iodine Intake in Pregnancy and Its Health Consequences: Systematic Review and Meta-analysis.Biological trace element research · 2023Pooled it
- Should iodine supplementation be universally recommended for pregnant women in Brazil? A position statement from the Thyroid Department of the Brazilian Society of Endocrinology and Metabolism (SBEM).Archives of endocrinology and metabolism · 2025Review
- Iodine Deficiency and Excess in Brazilian Pregnant Women: A Multicenter Cross-Sectional Study (EMDI-Brazil).Nutrients · 2025Article
- Diet quality and its relationship with iodine status in pregnant women living in a Brazilian region where table salt is iodine-fortified according to public health policies.Archives of endocrinology and metabolism · 2025Article
- Association between individual urinary iodine concentrations in pregnant women and maternal/newborn outcomes.Endocrine connections · 2025Article
- Urinary iodine concentration and thyroid function in pregnant women with hypertensive disorders.Frontiers in endocrinology · 2025Article
- Understanding the Pathogenesis of Gestational Hypothyroidism.Frontiers in endocrinology · 2021Review
- Review
- Effects of Metformin on TSH Levels and Benign Nodular Goiter Volume in Patients Without Insulin Resistance or Iodine Insufficiency.Frontiers in endocrinology · 2019Article
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Authors and funding
8 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
objectiveTo assess iodine status and its effects on maternal thyroid function throughout pregnancy.
designIn the present prospective cohort study, three urinary samples were requested for urinary iodine concentration (UIC) determinations in both the first and third gestational trimesters. Serum thyrotropin (TSH) and free thyroxine (FT4) were analysed in both trimesters and thyroid antibodies were assessed once.
settingRio de Janeiro, Brazil.ParticipantsFirst-trimester pregnant women (n 243), of whom 100 were re-evaluated during the third trimester.
resultsIodine sufficiency was found in the studied population (median UIC=216·7 µg/l). The first- and third-trimester median UIC was 221·0 and 208·0 µg/l, respectively. TSH levels (mean (sd)) were higher in the third trimester (1·08 (0·67) v. 1·67 (0·86) mIU/l; P<0·001), while FT4 levels decreased significantly (1·18 (0·16) v. 0·88 (0·12) ng/dl; P<0·001), regardless the presence of iodine deficiency (UIC<150 µg/l) or circulating thyroid antibodies. UIC correlated (β; 95% CI) independently and negatively with age (-0·43; -0·71, -0·17) and positively with multiparity (0·15; 0·02, 0·28) and BMI (0·25; 0·00, 0·50). Furthermore, median UIC per pregnant woman tended to correlate positively with TSH (0·07; -0·01, 0·14). Women with median UIC≥250 µg/l and at least one sample ≥500 µg/l throughout pregnancy had a higher risk of subclinical hypothyroidism (OR=6·6; 95% CI 1·2, 37·4).
conclusionsIn this cohort with adequate iodine status during pregnancy, excessive UIC was associated with an increased risk of subclinical hypothyroidism.
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