Infant And Child Health: NBER Research Summary

Why has the underlyinghealth or morbidity of newborns, as proxied by the rate of low birth weight births, remained so immovable? Even more baffling, why has there been so little change in newborn healththe rate of low birth weight despite increases in the inputs that we believe produce good health? Prenatal inputs that many contend should lower its incidence. Recent research by my colleagues and me suggests that previous estimates of the efficacy of many inputs designed to improve newborn health is probably inflated by favorable selection. The women who initiate prenatal care early, or who participate in WIC, are likely to be more motivated, less stressed, and more risk averse than the women who start care late or who do not participate in WIC. Too often we lack empirical methods for overcoming the problems caused by selection. In addition, in vetting their results, economists often neglect the clinical literature. Consider studies of the effect of programs to enhance maternal nutrition on infant health. Economic theory is helpful in specifying the demand for nutrition, but the effect of nutrition on fetal growth is a physiological, not an economic, relationship