Blood lead at currently acceptable levels may cause preterm labour

Journal of oral science

Volume 3 - Number

Article Type: ---- Unspecified ----

Objectives Although occupational and environmental exposures to lead have been dramatically reduced in recent decades, adverse pregnancy outcomes have been observed at 'acceptable' levels of blood lead concentrations (<= 10 mu g/dl). Methodology Blood samples were collected from 348 singleton pregnant women, aged 16-35 years, during the first trimester of pregnancy (8-12 weeks) for lead measurement by inductively coupled plasma-mass spectrometry. Subjects were followed up and divided into two groups (preterm and full-term deliveries) according to duration of gestation. Results The average (range) and geometric means of blood lead levels were 3.8 (1.0-20.5) and 3.5 mg/dl, respectively. Blood lead level was significantly (p<0.05) higher in mothers who delivered preterm babies than in those who delivered full-term babies (mean +/- SD: 4.46 +/- 1.86 and 3.43 +/- 1.22 mu g/dl, respectively). Logistic regression analysis demonstrated that a 1 unit increase in blood lead levels led to an increased risk of preterm birth (OR 1.41, 95% CI 1.08 to 1.84). Conclusion Adverse pregnancy outcomes may occur at blood lead concentrations below the current acceptable level.