This paper combines a theoretical and an empirical approach to address how health at birth affects child development. Using a simple theoretical model in which parents invest in their children, we identify the mechanisms through which better health at birth can improve child development. We also emphasise how parental socioeconomic status can shape the effects of health at birth. We perform an empirical analysis on a French cohort of children born in 2011, using a unique dataset ELFE. We identify the effect of birth weight and gestational age on child development at 1 year. The results indicate that only gestational age positively affects early development. We find no empirical evidence for the existence of a severity effect, according to which the adverse effects of poor health at birth are higher for children in low-income families or with poorly educated mothers.

本文结合了理论和实证方法来解决出生时的健康如何影响儿童发育。使用父母对孩子进行投资的简单理论模型，我们确定了改善出生时健康状况可以改善儿童发育的机制。我们还强调父母的社会经济地位如何影响出生时的健康。我们使用独特的数据集 ELFE 对 2011 年出生的法国儿童队列进行了实证分析。我们确定了出生体重和胎龄对 1 岁时儿童发育的影响。结果表明，只有胎龄对早期发育有积极影响。我们没有发现严重性效应存在的经验证据，