Do Postpartum Maternal Iodine Status or Supplementation Affect Thyroid Function After Delivery? A Systematic Review and Meta-Analysis

source extracted confidence: high 2026-04-09
#humans #iodine #female #postpartum-period #dietary-supplements

Do Postpartum Maternal Iodine Status or Supplementation Affect Thyroid Function After Delivery? A Systematic Review and Meta-Analysis

Nazeri et al., 2024 | Biol Trace Elem Res | Meta Analysis

Citation

Nazeri Pantea, Pearce Elizabeth N, ... Azizi Fereidoun. Do Postpartum Maternal Iodine Status or Supplementation Affect Thyroid Function After Delivery? A Systematic Review and Meta-Analysis. Biol Trace Elem Res. 2024-Aug;202(8):3425-3441. doi:10.1007/s12011-023-03934-3

Abstract

The aim of this systematic review and meta-analysis was, for the first time, to explore whether postpartum maternal iodine status or supplementation is associated with thyroid function after delivery. The MEDLINE/PubMed, Web of Science, Embase, and Scopus were searched up to December 2021 to identify relevant studies. The pooled mean thyroid stimulating hormone (TSH), free thyroxine (fT4), and thyroxine (T4) concentrations and 95% confidence intervals (CIs) were estimated based on maternal urinary iodine concentration (UIC) (< 50, 50-100, 100-200, and > 200 µg/L) or breast milk iodine concentration (BMIC) (< 100 µg/L vs. ≥ 100 µg/L) during postpartum. A fixed/random effects model was used based on the absence/presence of heterogeneity, respectively. The study is registered with PROSPERO, number CRD42022336145. A total of 2175 studies were identified, of which 18 were eligible for the meta-analysis. The pooled values for TSH, fT4, and T4 concentrations in all subgroups were within the normal range; however, except for TSH, comparing the 95% CI showed no statistically significant difference among different subgroups. The pooled mean for TSH concentration in women with UIC > 200 µg/L was 2.23 mIU/L, whereas the corresponding values in women with UIC < 50, 50-100 and 100-200 µg/L were 0.56, 0.56 and 0.95 mIU/L, respectively. Thyroid hormones in women with BMIC < 100 µg/L and ≥ 100 µg/L were within the normal range. Iodine supplementation during postpartum was not associated with any differences in thyroid parameters, compared to non-supplemented women. In conclusion, iodine status or supplementation had no effect on thyroid hormones in postpartum women.

Key Findings

In conclusion, iodine status or supplementation had no effect on thyroid hormones in postpartum women.

Outcomes Measured

  • Requires manual extraction

Population

Field Value
Population See abstract
Sample Size 2175
Age Range See abstract
Condition See abstract

MeSH Terms

  • Humans
  • Iodine
  • Female
  • Postpartum Period
  • Dietary Supplements
  • Thyroid Gland
  • Thyroxine
  • Thyrotropin
  • Pregnancy

Evidence Classification

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

Provenance

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