Background

There is evidence of a weak placental-fetal barrier to lead, suggesting that maternal lead exposure could affect the fetus. The health consequences for newborns from in utero lead exposure are not well understood.

Objectives

We estimated the effects by trimester, of short-term (<1 week), airborne lead exposure during pregnancy on birth outcomes.

Methods

We use quasi-experimental variation in airborne lead exposure during pregnancy, based on NASCAR’s deleading of racing fuel in 2007, in a difference-in-differences model, to estimate the effect of deleading on the birth outcomes of all live births (n = 147,673) in the Charlotte-Concord-Gastonia Metropolitan Statistical Area between 2004 and 2009.

Results

After deleading, children born to mothers residing <4000 m of Charlotte Motor Speedway (relative to those residing >10,000 m) experienced an average increase in birthweight (BW) of 102.50 g [P < 0.001]. The probability of low birthweight (LBW) declined by 0.045 [P = 0.001], preterm (PRE) births by 0.03 [P = 0.04], and small for gestational age (SGA) by 0.04 [P = 0.002]. We find that benefits accrue primarily in preterm LBW and SGA babies, and from decreased lead exposure in the first trimester.

Conclusions

Short-term exposure to airborne lead during pregnancy adversely affects birth outcomes. Reducing even very brief exposure to airborne lead during pregnancy may improve birth outcomes.

中文翻译：

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怀孕期间短期空气中的铅暴露会影响出生结果吗？NASCAR 去领先政策的准实验证据

背景

有证据表明胎盘-胎儿对铅的屏障较弱，这表明母亲接触铅可能会影响胎儿。子宫内铅暴露对新生儿的健康影响尚不清楚。

目标

我们评估了妊娠期间短期（<1 周）空气中铅暴露对出生结果的影响。

方法

我们根据 2007 年 NASCAR 赛车燃油除铅情况，在双重差分模型中使用怀孕期间空气中铅暴露的准实验变化来估计除铅对所有活产儿出生结果的影响（n = 147,673） ）2004 年至 2009 年夏洛特-康科德-加斯托尼亚大都会统计区。

结果

去铅后，居住在夏洛特赛车场 <4000 m 的母亲所生的孩子（相对于居住在 >10,000 m 的母亲），出生体重 (BW) 平均增加了 102.50 g [P < 0.001]。低出生体重 (LBW) 的概率下降了 0.045 [P = 0.001]，早产 (PRE) 的概率下降了 0.03 [P = 0.04]，小胎龄 (SGA) 的概率下降了 0.04 [P = 0.002]。我们发现，主要受益于早产的低出生体重和 SGA 婴儿，以及妊娠前三个月铅暴露的减少。

结论

怀孕期间短期接触空气中的铅会对出生结果产生不利影响。怀孕期间即使是非常短暂地减少空气中铅的接触也可能会改善出生结果。