Aim: To evaluate the extent of social variation in pregnancy outcome in the Czech Republic, compared to Sweden. Material and methods: All live births resulting from singleton pregnancies in 1989 - 1991, reported to the Czech birth registry (n = 380 633) and to the Swedish birth registry (n = 351 796) were linked to the death register and studied with respect to social variation in birth weight, preterm delivery (< 37 weeks of gestation) and postneonatal mortality (28 - 365 days). The results are adjusted for maternal age, parity, and other potential confounders. Results: The mean birth weight was significantly lower in the Czech population (3310 g vs 3522 g, p < 0.001). Maternal education and marital status were important determinants of birth weight, preterm birth and postneo- natal mortality in both populations. The extent of social variation in birth weight and preterm birth was greater in the CR. Adjusted for maternal age, parity, and sex of the infant, the difference in mean birth weight of infants born to primary educated compared to university educated mothers was 197 g (95% CI 190 to 205 g) in the Czech population and 138 g (95% CI 131 to 146 g) in the Swedish population. The odds ratio for preterm birth, adjusted for maternal age, parity and sex of infant, in infants born to primary versus university educated mothers was 2.19 (95% CI 2.04 - 2.35) in ČR and 1.53 (95% CI 1.43 - 1.64) in Sweden. The odds ratio for postneonatal death between children born to mothers with basic compared to secondary education, adjusted for maternal age, parity and sex and birthweight of the infant, was 1.86 (95% CI 1.54 - 2.24) in CR and 1.42 (1.13 - 1.78) in Sweden. Conclusion: The socioeconomic variation in birth weight, frequency of preterm birth and postneonatal mortality is greater in the Czech Republic than in Sweden.

        Key words: birth weight, preterm birth, postneonatal mortality, socioeconomic factors, Czech Republic, Sweden