Association of maternal blood lead concentration with the risk of small for gestational age: A dose-response meta-analysis

Abstract

In spite of growing evidence for the negative effect of lead, knowledge about the dose-response relationship of maternal blood lead level (BLL) and the risk of small for gestational age (SGA) is limited. We performed this meta-analysis to evaluate the dose-response relation between maternal BLL and the risk of SGA. A systematic search through Embase and PubMed was performed. Odds ratios (ORs) and 95% confidence intervals (95% CI) were calculated. The nonlinear and linear relationships between maternal BLL and the risk of SGA were also investigated. Results from 51,065 patients showed a significant association between maternal BLL and risk of SGA in highest versus lowest analysis (OR: 1.54; 95% CI: 1.12–2.10, p = 0.007). While there was no association in linear dose-response (OR: 1.02; 95% CI: 1.00–1.04, p = 0.021) meta-analysis, a direct relationship was observed in the nonlinear model (nonlinearity p < 0.001). Results of this dose-response meta-analysis showed that maternal BLL higher than ∼ 0.3 µg/dL is directly associated with the risk of SGA.

Keywords:

• Blood lead
• dose-response meta-analysis
• lead poisoning
• small for gestational age

Disclosure statement

The authors declare no competing financial interests.

Additional information

Funding

This study was supported by the Students' Scientific Center, Tehran University of Medical Sciences, Tehran, Iran [grant number: 98-3-104-45236] received by the first author.