Should all pregnant women be screened for hepatitis B surface antigen?

One thousand, one hundred and ninety-three pregnant women were screened for hepatitis B surface antigen (HBsAg) carriage after their histories had been reviewed to assess their risk status. In this prospective study, carrier rates were examined according to conventional risk criteria and also according to extended criteria that included the country of birth of the patient's parents. Twenty-six (2.2%) patients were found to be HBsAg seropositive, and one of these patients showed no identifiable risk factors. In four hepatitis B virus carriers, the only risk factor was that the patients' parents had been born in a country that was classified as high risk. Thus, five (19%) of 26 patients would not have been identified by means of previously-accepted screening procedures. Four hundred and forty-two (37%) patients showed at least one conventional risk factor and 558 (47%) patients showed at least one risk factor by our extended criteria. Given the high costs to the community of chronic hepatitis B virus carriage, it was concluded that the screening of all antenatal clinic patients for the presence of HBsAg is cost effective.