Early pregnancy blood lead levels and the risk of premature rupture of the membranes.

To clarify the effects of lead on fetal premature rupture of the membranes (PROM), blood lead concentrations were measured using inductively coupled plasma-mass spectrometry in 332 women, aged 16-35 years, during their early pregnancy period (8-12 weeks). Blood lead concentrations were significantly higher in the 36 PROM deliveries than in the 296 non-PROM deliveries (mean ± SD, 4.61 ± 2.37 and 3.69 ± 1.85 μg/dl, respectively; p<0.05). The logistic regression analysis revealed that a 1-unit increase in the logarithm of the blood lead level led to a several-fold increase in the risk of PROM (unit risk=17.98, 95% CI 1.6-198.6). Thus, it is suggested that lead can increase the risk of PROM in pregnant women with mean blood lead less than 5 μg/dl.