and more likely to drink alcohol. Although judgement on the role of these mechanisms connecting violence shocks and newborn health is inevitably speculative, the evidence here exposes the importance of behavioral responses, in addition to the purely biological effects induced by violence-related stress.

The next section reviews empirical studies in economics examining the fetal origins hypothesis and particularly those that have specifically addressed war-violence shocks. Section III gives a brief overview of the Colombian conflict. Section IV describes the data and presents the methodological details of the analysis. The results are presented in the following section. The conclusion at the end summarizes and highlights avenues for future research.

# **II. Literature review**

The fetal-origins hypothesis states that shocks to the environment in utero alter the physiology and metabolism of the fetus, with effects apparent at birth<sup>4</sup> and lifelong consequences (Almond and Currie 2011; Johnson and Schoeni 2011). While this literature started in the biomedical field, the economic discipline has contributed in two main fronts, as described in Almond and Currie (2011). First, it formalized the notion of the observed net effect of an in utero shock depending on the balance of two opposing forces. On the one hand, the scarring effect is the deterioration of fetal health produced by the shock. On the other hand, if there is higher fetal mortality at the lower end of the fetal health distribution, the sample of live births for whom the effect of the shock is measured would be smaller and selected; the culling or selection effect refers to the better average observed health in this surviving cohort. Whether the survivors are healthier or weaker has implications for explaining inequality patterns of later-life outcomes. The second contribution of the economic discipline to this literature has been empirical, broadening the variety of shocks analyzed. A subset of this literature focuses on violence. Some studies look at criminal violence (Dustmann and Fasani 2016; e.g. Foureaux-Koppensteiner and Manacorda 2016), but I concentrate the review on those emphasizing violence in conflict-affected countries.<sup>5</sup> I also concentrate on the short-term impacts of violence exposure in utero, although other studies (e.g. Akresh et al. 2012; Akresh, Lucchetti, and Thirumurthy 2012; Tranchant, Justino, and Müller 2020) indicate that in utero effects can last through childhood, and that there are negative health consequences of exposure to war violence at other stages in life.

Camacho (2008) analyzes the Colombian case using birth records from the Vital Registration System (VRS) (1998 to 2003) and municipal landmine explosions data. She finds that a landmine explosion occurring during the first trimester of pregnancy in the municipality where the mother resides is associated with a reduction in birthweight of 8.7 gr, while there was no effect for explosions in the second or third trimesters. Using a similar empirical specification, Mansour and Rees (2012) look at the al-Aqsa Intifada in the West Bank using DHS data and district-level fatalities caused by Israeli security forces as the violence measure. The authors find that exposure

> 4 For instance, fetal alcohol syndrome, wherein the newborn's facial features reflect the mother's alcoholism, or stunted or missing limbs associated with the intake of thalidomide, a once commonly prescribed medicine for morning sickness (Almond and Currie 2011).

> 5 This also excludes studies that analyzed a one-off, large-scale event (e.g. the September 11 attacks (Currie and Schwandt 2016)).

4