Heavy Metal Index
Ask the IndexAboutIndex Pro

Meta-analysis of maternal exposure to heavy

Source

This source page is a mechanical bulk-ingest record for a PDF in the research-pulls corpus.

Author Karen Pendergrass · ORCID 0000-0002-2348-7259UPDATED 2026-08-03Cite this pageVersion historyDownload PDF
Page snapshot
Cited by7 pages
Metals measured4
Evidence tierB
Year2026

Overview

This source page is a mechanical bulk-ingest record for a PDF in the research-pulls corpus. It preserves source-level identity, routeable product/analyte scope, and exact extracted numeric lines for later human or fresh-context audit. It does not derive HMTc thresholds, percentiles, or brand-by-brand comparisons.

Key numbers

The worker extracted the full PDF text with layout preservation twice and compared extraction hashes before commit. The following lines are copied from numeric/table-bearing regions of the PDF and retain the source units and wording where legible:

  • association of Pb concentration with preterm birth (OR = 1.4, 95% CI: 1.17, 1.68; P < 0.001) and SGA (OR = 1.66, 95% CI:
  • 1.04, 2.66; P = 0.034), though not with LBW. Cd concentration was associated with LBW (OR = 1.10, 95% CI: 1.00, 1.20;
  • P = 0.041) and SGA (OR = 1.27, 95% CI: 1.08, 1.48; P = 0.003), but not with preterm birth. No significant association was
  • ing for 9.8% of all live births. On average, one in ten new- Reporting Items for Systematic Reviews and Meta-
  • Numerous epidemiological studies suggest a poten- (ORs) and 95% confidence intervals (CIs); (iv) Study
  • Quality evaluation name), involving 52,390 subjects. The age ranged from 22
  • CIs were summarized to evaluate the correlation of included. The pooled results, using an REM (I2 = 79.5%,
  • Q statistic. Significant and substantial heterogeneity was (OR = 1.4, 95% CI: 1.17, 1.68; P < 0.001) (Fig. 2A).
  • model (FEM) was utilized. Subgroup analysis was per- porated. The pooled results, using an REM (I2 = 81.7%,
  • substantial heterogeneity was present, we examined its Cd levels with preterm birth (OR = 1.23, 95% CI: 0.91,
  • Sensitivity analysis was conducted by omitting indi- included. The pooled results, using an REM (I2 = 63.6%,
  • the results. If the effect size remained within the origi- higher Hg levels and preterm birth (OR = 1.15, 95% CI:
  • below 0.05 was considered statistically significant. Analysis of this outcome, with I2 = 56.5% and p = 0.075 in
  • results displayed no significant association between passed. Analysis of this outcome, with I2 = 41% and
  • Pb and LBW (OR = 1.00, 95% CI: 0.74, 1.34; P = 0.998) p = 0.166 in heterogeneity analysis, adopted an REM.
  • Three studies encompassing 23,391 subjects were 95% CI: 1.08, 1.48; P = 0.003) (Fig. 4B).
  • incorporated. Analysis of this outcome, with I2 = 0.00%
  • (OR = 1.10, 95% CI: 1.00, 1.20; P = 0.041) (Fig. 3B). analyzed due to an insufficient number of articles. Only
  • Pb and SGA (OR = 1.4, 95% CI: 1.17, 1.68; P < 0.001) and Cd (OR = 1.23,
  • Five studies were included (four studies remaining after 95% CI: 0.91, 1.67; P = 0.185) was observed. No associa-
  • of this outcome, with I2 = 84% and p < 0.001 in heteroge- 95% CI: 0.91, 1.44; P = 0.24). Regarding LBW, a signifi-
  • neity analysis, applied an REM. The pooled results indi- cant correlation with higher levels of Pb (OR = 1.00, 95%
  • cated a significant correlation of higher Pb levels with CI: 0.74, 1.34; P = 0.998) and Cd (OR = 1.10, 95% CI: 1.00,
  • an elevated risk of SGA (OR = 1.66, 95% CI: 1.04, 2.66; 1.20; P = 0.041) was discovered. Regarding SGA, a signifi-
  • P = 0.034) (Fig. 4A). cant association with higher levels of Pb (OR = 1.66, 95%
  • CI: 1.04, 2.66; P = 0.034) and Cd (OR = 1.27, 95% CI: 1.08, was discovered between higher Hg concentrations and
  • vated Pb concentrations demonstrated significant associ- were found to be stable (File S5.6.1-2.1). Publication bias
  • cohort studies (OR = 1.38, 95% CI: 1.13, 1.70; P = 0.02), trim-and-fill was 1.058 (95% CI: 0.881, 1.272, P = 0.545).
  • (OR = 1.31, 95% CI: 1.03, 1.67; P = 0.029), but no asso- Pb and preterm birth, SGA, and LBW
  • higher risk of preterm birth in Asia (OR = 1.40, 95% CI: However, there are inconsistencies in the subgroup analy-
  • with increased preterm birth risk in T3 (OR = 1.22, 95% may be due to different article inclusion criteria (this
  • CI: 1.08, 1.38; P < 0.001) and T1 T2 (OR = 5.88, 95% CI: meta-analysis excluded articles whose original data had
  • related to the small number of case-control studies incor- geneity was observed (I²=56.5%), but a subgroup analysis
  • birth, while urine and umbilical cord specimens are not. correlation with LBW (OR = 1.00, 95% CI: 0.74–1.34).
  • placenta’s ability to transport nutrients, for example. Pb (OR = 1.27, 95% CI: 1.08–1.48, P = 0.003), consistent with
  • levels (reflecting recent exposure) more strongly predict OR value of Cd exposure was 1.23 (95% CI: 0.91–1.67,
  • regarding GA. Pb exposure limits the supply of nutrients 1.15 (95% CI: 0.91–1.44, P = 0.24), consistent with Pan
  • foods and stainless steel or alloy tableware can help pre- ond trimester (T2). Defining reference ranges and safety
    1. Jelliffe-Pawlowski LL, Miles SQ, Courtney JG, Materna B, Charlton V. Effect of al. Recommended acceptable levels of maternal serum typical toxic metals

Methods (brief)

  • ited sample size warrants cautious interpretation of these ture with logarithmically transformed original data and
  • and skin contact. Hg is volatile in its normal state. For Cd with LBW, and considering that the blood sample

Implications

This page makes the source discoverable for category-level evidence routing. Values remain source-native and should be used only with the stated matrix, species, basis, geography, and censoring context from the paper. The page does not convert total mercury to methylmercury or use total arsenic as inorganic arsenic.

Wiki pages this source may touch

Verification notes

  • Identity check: DOI, raw handle, candidate cite-key, and SHA-256 were compared against existing wiki/sources/ pages before creation.
  • Full-PDF read: pdftotext -layout was run on the full PDF twice; extracted text hashes matched before the page was written.
  • Numeric verification: numeric/table-bearing lines were selected mechanically from the verified extraction and preserved without unit conversion or rounding.
  • Brand firewall: the worker skips PDFs when extracted numeric lines appear brand/manufacturer-sensitive; this page contains category-level or species-level evidence only.
  • HMTc firewall: no threshold, percentile, pass/fail, clean/dirty, or certification math is stated.

Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.

CommitDateChangeDescription
b01ec52c2026-08-04major2 sections added
d49e450f2026-08-03major5 sections added; narrative text revised