Parental exposure to lead and small for gestational age births.

BACKGROUND: Previous studies about the effect of lead exposure on adverse birth outcomes are still inconsistent and few studies estimate the relationship between parental lead exposure and small for gestational age (SGA) infants. An occupational cohort study to assess whether parental lead exposure would be related to decreased birth weight and shortened gestational ages of their offspring was conducted. Whether higher lead exposure doses would increase risks of low birth weight (LBW), preterm delivery, and SGA births was also investigated.

METHODS: A Program to Reduce Exposure by Surveillance System-Blood Lead Levels (Press-BLLS) was established in Taiwan in July 1993. The names of workers exposed to lead was collected from this occupational blood-lead notification database. The birth outcomes of their offspring were determined by linking to the Taiwan birth registration database from 1993 to 1997. Only singleton births whose parental blood-lead concentrations were tested during pregnancy or prior to conception, or within a 1-year span before these two periods were included.

RESULTS: Among 1,611 eligible births, 72 births were LBW, 74 were preterm deliveries, and 135 were SGA. Maternal blood-lead concentrations (PbBs) equal to or more than 20 microg/dl had a higher risk of mothering a SGA child (risk ratio (RR) = 2.15; 95% confidence interval (CI), 1.15-3.83).

CONCLUSIONS: Additional evidence of the effects of lead on adverse birth outcomes, especially for SGA births is reported. Maternal exposure to lead plays a more important role in the adverse effect on birth outcome than does paternal exposure.