Development of occult hepatitis B viral infection in pregnancy: implications for antenatal screening in women from endemic areas.

Occult hepatitis B virus (HBV) infection, manifest clinically by the presence of HBV deoxyribonucleic acid (HBV DNA) in peripheral blood in individuals who test negative for the HBV surface antigen (HBsAg), may occur in various clinical contexts, including under the influence of pharmacological immunosuppression in patients from areas endemic for HBV and, hence, at risk of previous exposure. Pregnancy is a condition associated with immune suppression, but whether virus-specific immunity may be suppressed to an extent sufficient to allow occult HBV infection to develop is currently unknown. This is potentially relevant not only to the mother's health but also because vertical transmission has been reported in the occult HBV infection setting.