Risk factors associated with hepatitis B infection in antenatal patients.

Risk factors associated with HBsAg carriers were prospectively examined in 1821 women attending the Antenatal Clinic of an inner-city obstetrics hospital. Of the sample, 3.2% were HBsAg carriers and 28.7% of 725 tested for anti-HBs were positive. Birth in a country where the prevalence of HBsAg is high and Aboriginal ancestry were the major associated factors rather than a past history of hepatitis or intravenous drug use. Women from Indochina or the Pacific region, if HBsAg-positive, were more likely than other carriers to have markers of viral replication including HBeAg, hepatitis B virus (HBV) DNA, and DNA polymerase. Evidence of past infection with HBV also varied with country of birth, but 11% of women with no apparent risk factors for prior HBV infection were anti-HBs positive. This study indicates the need for a screening programme for HBsAg in antenatal populations.