摘要:Background: Vertical transmission of hepatitis B virus (HBV) from infected mothers to their neonates is one of the most important routes of infection. The exact prevalence rate of HBV in Iranian pregnant mothers is not well known but based on different studies it is estimated between 0.35% and 6.5%. The aim of this study was to determine the seroprevalence of hepatitis B surface antigen (HBsAg) in pregnant women of selected provinces in Iran. Methods: At this cross-sectional study, seven provinces supposed to be of high and low prevalence of hepatitis B in the general population selected. Multistage sampling was used to enroll 5261 parturient women who attended the target provinces birth facilities, during January to March of 2011, were recruited to study. To determine the statistically significant mean and proportion differences, t -test and χ 2 test were used, respectively. Results: Overall 1.2% was positive HBsAg of which 11% of them were hepatitis B e-antigen positive as well. The eastern and north eastern provinces were considerably higher in HBsAg seropositivity than the west and northwest of the country. Conclusions: In view of the considerable prevalence of hepatitis B in pregnant women, screening all pregnant women prioritizing the eastern and north-eastern provinces is strongly recommended.