Aim: To assess secular trends in birth weights of liveborn infants in Croatia from 1983 to 2003.
Methods: Of a total of 959,591 liveborn infants in the study period, 384,367 were born in the prewar (1983-1989), 226,226 during the war (1991-1995), and 348 998 in the postwar (1996-2003) period. The birth weight of liveborn infants was assessed by 500 g weight groups on the basis of data provided by the Croatian National Institute of Public Health.
Results: The gradual and significant increase in the share of infants with birth weight > or =3500 g (<0.001) was paralleled by a reduction in the share of infants with birth weights 2500-3449 g (P<0.001) and <2500 g (P<0.05) in the study period. There was a positive trend in the proportion of 4000-4499 g, > or =4500 g (P<0.001 for both), and 500-999 g (P=0.002) birth weight groups and negative trend in 1000-1499 g, 2500-2999 g, and 3000-3499 g weight groups (P<0.001 for all). During the war period, the proportion of liveborn infants in the 2500-3499 g weight group decreased in comparison with prewar proportion; this trend continued in the postwar period (P<0.001 for both). In the war period, the proportion of liveborn infants with birth weights of 2000-2499 g was significantly larger (P<0.001) and that of > or =4500 g significantly smaller in comparison with the prewar and postwar proportions (P<0.001 for both).
Conclusion: Positive secular changes in infant birth weights observed in the prewar and postwar period contrasted negative changes during the war period in Croatia. This finding may suggest the association between war suffering and stress and changes in birth weights of newborns.