In Utero Shocks and Health at Birth: The Distorting Effect of Fetal Losses
研究子宫内冲击对出生健康的影响时，若冲击改变胎儿死亡概率且死亡与存活胎儿存在健康差异，标准方法会产生偏差。以热浪对出生体重的影响为例，考虑胎儿选择效应后热效应显著增大，提示政策评估需纳入胎儿损失扭曲效应。
Abstract Research on the effect of in utero shocks on health at birth may be influenced by in utero selection. This study outlines a conceptual framework and shows that the results of the standard empirical approach are biased if (i) the exposure changes the probability of fetal death and (ii) health differences exist between deceased and surviving fetuses. Furthermore, an empirical example is provided to illustrate the potential importance of fetal selection. Examining the effect of heat on birth weight, I find that accounting for fetal selection substantially increases the heat effect compared to the standard approach. These results suggest that, in some cases, incorporating the distorting effect of fetal losses into the estimations may be critical to providing more informed guidance for public policy.