Prenatal stress during the 1999 bombing associated with lower birth weight—a study of 3,815 births from Belgrade

During the 3-month bombing of Serbia (March 24–June 9, 1999), the entire population, including pregnant females as an especially vulnerable group, was exposed to a high degree of stress. This is the first study to explore the effects of prenatal stress during the 1999 bombing of Belgrade on the main obstetric characteristics of newborns. The design of the study was retrospective cross-sectional. The total number of birth records in the sample was 3,815, namely, 1,198 from the group exposed to prenatal stress and 1,251 and 1,366 from the respective control periods, years 1996 and 2003, when no stressful events affected the city. We found that exposed mothers gave birth to infants with statistically significantly lower birth weight (BW; mean difference = 86 g, 95% confidence interval = 67 to 104; F _{(1, 3,349)} = 80.8, p < 0.001, η _p ²  = 0.024), when controlling for confounding effects of body length and head circumference. There was no specific relation between the trimester of stress exposure and BW in infants born in 1999. Neither increased frequency of preterm deliveries nor more complications of pregnancy and delivery were found in the given sample. Possible consequences of lower BW on psychosocial and somatic functioning should be evaluated through the lifetime.