The Effect of Temperature Shocks on Health at Birth

In this research we analyze the effect of extreme temperature during the pregnancy on the outcomes of live births in Hungary. Birth registry data of more than 5 million newborns between 1970 and 2010 are matched with daily temperature data. Matching is based on the place of residence of the mother at the time of the delivery. Birth registry data that covers the entire population come from the Hungarian Central Statistical Office, whereas city-level weather data come from the Hungarian Meteorological Service. We calculate indicators of extreme temperature (e.g. the number of extremely hot days) for each trimesters of the pregnancy. Our dependent variables are birth weight, low birth weight, Apgar score, birth length, and pre-term birth. Although variation in weather over time is exogenous, we are able to control for important socio-demographic factors that might influence newborns’ health, and even for unobserved time-invariant mother characteristics by performing mother-fixed effects estimates. In this way our study identifies causal effects.

Our main research question is whether temperature shocks (defined as occurrence of extremely hot/cold days) in utero influence health at birth. The second research question is the following: in which trimester is this relationship the strongest? Finally, we try to answer the question: how do the estimated effects differ between high- and low-status families?

In one hand, this study adds to the large and growing literature studying the effects of fetal conditions on short- and long-term outcomes (e.g. health at birth, education, labor market success, etc.). On the other hand, our research is also related to the literature analyzing the impacts of global climate change.