Objectives: The main objective was to determine whether there is a difference in the health behavior of pregnant women before and during pregnancy. Study design: A cross-sectional study. Methods and participants: Participants were pregnant women who came to the gynecological examinations at the six specialist gynecological practices on the premises of the Osijek Health Center. Survey questionnaires were completed by 221 pregnant women. Results: The average age of pregnant women is 31. The results show that 64.7% of the examinees are recreationally engaged in some sports activity (walking, speed walking, jogging, dancing), unlike before pregnancy when 31.2% of the same women were recreationally or professionally engaged in sports. The average weight gain in the first trimester is 1 kg, in the second trimester 5 kg, and in the third trimester 11 kg. In addition to reducing fast food during pregnancy, sweeteners (chocolate, cake, biscuits) and salty snacks (chips, sticks, crackers, popcorn) have also been reduced and the intake of fruits, vegetables and fish has been increased. 24 (11%) examinees consumed alcoholic drinks once or twice a month before pregnancy. 17 (7.8%) examinees consumed alcohol once a week before pregnancy, and only 2 examinees (0.9%) consumed alcohol once a week during pregnancy. Before pregnancy, 41.4% of women smoked, 42.8% of them quit smoking when they found out they were pregnant. Conclusion: Based on the research conducted, it is possible to conclude that there is a difference in the behavior of pregnant women before and during pregnancy.