We analyze the impact of in utero temperature exposure on the birth weight and an indicator for low birth weight using administrative data on singleton live births conceived between 2000 and 2016 in Hungary. We find that exposure to high temperatures during pregnancy decreases birth weight, but its impact on the probability of low birth weight is weaker. Exposure to one additional hot day (mean temperature > 25 °C) during the gestation period reduces birth weight by 0.46 g, relative to a 15–20 °C day. The second and third trimesters appear to be slightly more sensitive to temperature exposure than the first trimester. We project that climate change will decrease birth weight and increase the prevalence of low birth weight by the mid-twenty-first century. The projected impacts are the strongest for newborns conceived during the winter and spring months.

我们使用在2000年至2016年期间在匈牙利构思的单胎活产的行政数据，分析了宫内温度暴露对出生体重的影响以及低出生体重的指标。我们发现，怀孕期间暴露于高温会降低出生体重，但对低出生体重可能性的影响则较弱。相对于15–20°C的一天，妊娠期再接触一个炎热的一天（平均温度> 25°C）可使出生体重减少0.46 g。孕中期和孕中期似乎比孕早期稍微更敏感。我们预计，到21世纪中叶，气候变化将减轻出生体重，并增加低出生体重的患病率。