PARENTAL EXPOSURE TO LEAD AND ADVERSE BIRTH OUTCOMES

Abstract

Introduction There is still debate on whether lead exposure is relative to adverse birth outcomes. We utilized the occupational blood lead notification database to obtain blood lead levels (PbBs) as an indicator of exposure and tried to assess whether offspring of parents occupationally exposed to lead would have an increased risks of low birth weight, preterm births, and small for gestational age (SGA). Methods The occupational blood lead notification database was primarily designed for regular monitoring of lead-exposed workers who by law should be examined annually. Information of birth outcome was obtained from the Taiwan birth certificate database, which was based on the compulsory notification of all live births of 20 completed weeks gestation or more. All births to lead-exposed workers were identified by matching information from two databases. We excluded multiple pregnancies because these newborns were more likely to be born earlier. The linkage yielded 1,611 eligible singletons born during 1994 to 1997. Low birth weight was defined as a birth weight of less than 2,500g, preterm delivery meant a gestational age of less than 37 weeks, and SGA was defined as a birth weight below the 10th percentile of gender-specific birth weight for gestational age. We employed multiple logistic models to investigate the associations between PbBs and low birth weight, preterm delivery or SGA. Results Maternal PbBs during pregnancy more than 30 £gg/dl had a higher risk of mothering a child of SGA (odds ratio (OR) = 3.01, 95% confidence interval (95% CI) = 1.36–6.69) and both of parents with PbBs during spermatogenesis prior to conception or during pregnancy more than 30 £gg/dl had a higher risk of having a child of SGA (OR = 5.41, 95% CI = 1.31–22.33). The odds ratio of low birth weight was gradually but not significantly increased with elevated maternal PbBs. There also was an increase of having a child of preterm birth (OR = 1.91, 95% CI = 1.03–3.55) in mothers with PbBs during pregnancy more than 30 £gg/dl. Conclusions Our data indicated that offspring of mother or father who had higher blood lead levels during pregnancy or spermatogenesis would have a risk of adverse birth outcomes. The main limitations were lack of occupational history and inability to control other possible confounders.