Maternal smoking during pregnancy and birthweight: a propensity score matching approach.

There is accumulated evidence of the existence of a deleterious effect of smoking on birth outcomes. Understanding the effect of smoking on pregnancy is a critical issue because of the public policy implications for dissuading maternal smoking. We explore this issue by using the propensity score method and compare that with parametric estimators. First we estimate the treatment effect of smoking during pregnancy on different birth outcomes, by race. Then, we extend the method to the case of the multi-treatment "intensity of smoking." The deleterious effect of smoking is found robust to the different estimation methods used.