Summary
Cross-sectional study of 96 mother-newborn pairs in Ecatepec de Morelos, Mexico City Metropolitan Area, 2015-2016. Scalp hair sampled from both mothers and newborns at birth. Antimony was detected in 98.9% of maternal and 96.3% of newborn hair samples. Maternal hair Sb concentrations were substantially higher than newborn hair Sb concentrations (medians 18.0 vs. 1.0 ng/g), and the mother-newborn correlation for Sb was not statistically significant, unlike the significant correlations seen for lead (rho = 0.30), arsenic (rho = 0.70), and mercury (rho = 0.74). Maternal hair Sb was approximately two-fold higher than reference values reported for non-exposed pregnant women in Spain, with the maximum at 2870 ng/g (consistent with high point-source exposure from an outlier).
Key numbers
Maternal scalp hair Sb (ng/g dry weight), N = 96, Mexico City:
- Detection frequency: 98.9%
- P25: 12.2 ng/g
- Median: 18.0 ng/g
- P75: 29.0 ng/g
- Minimum: 3.0 ng/g
- Maximum: 2870.0 ng/g (extreme outlier; right-skewed distribution)
Newborn scalp hair Sb (ng/g dry weight), N = 96:
- Detection frequency: 96.3%
- P25: at or below LOQ (less than 0.060 ng/g)
- Median: 1.0 ng/g
- P75: 1.9 ng/g
- Maximum: 10.0 ng/g
Mother-newborn correlation for Sb: not statistically significant (unlike lead (Pb), arsenic (As), mercury (Hg) which were significant), suggesting limited Sb transfer to newborn hair.
Concentration rank order:
- Mothers: cadmium (Cd) less than As less than uranium (U) less than Sb less than Hg less than V less than Pb less than B
- Newborns: U less than Cd less than As less than V less than Sb less than Hg less than Pb less than B
PCA: Sb clustered with Ca, B, U in mothers (PC1) and with Cd, Pb, U in newborns (PC2).
Comparison with reference ranges:
- Maternal hair Sb approximately 2-fold higher than reference values for non-exposed pregnant women in Spain
- Newborn hair Sb within reference values for non-exposed children under 14 years
Evidence Fitness
Reconstructable dataset for hair Sb in a Mexico City megacity population. The lack of a significant mother-newborn correlation for Sb is informative about transplacental transfer pathways. The extreme maximum (2870 ng/g) is consistent with occupational or point-source industrial exposure in one participant.
Methods (brief)
Cross-sectional; 96 mother-newborn pairs, Hospital Dr. Jose Maria Rodriguez, Ecatepec de Morelos, Mexico City Metropolitan Area, August 2015-March 2016. Scalp hair cut at birth; 3 cm proximal segment. Metals by ICP-MS. Statistical: Spearman correlations, PCA.
Implications
- Certification: hair Sb in Mexico City mothers is approximately 2x above European background, consistent with higher industrial/urban Sb exposure. Limited transplacental transfer evidenced by weak mother-newborn correlation.
- Courses: illustrates that hair metal mother-newborn correlations are metal-specific and that Sb does not behave like lead or mercury in this matrix.
- App: not applicable.
- Microbiome: not addressed.
Provenance notes
Open access, CC BY. File from PMC OA S3 (PMC13331732). Samples collected 2015-2016; published 2026.
Update history
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