Vertical transmission of hepatitis B surface antigen in Saudi Arabia.

The prevalence of hepatitis B surface antigen (HBsAg) was studied in 3020 pregnant Saudi women. All the sera of 119 (3.9%) HBsAg-positive asymptomatic carrier mothers were titrated for HBsAg and investigated for hepatitis Be antigen (e-Ag) and its antibody (anti-e-Ag). Only 13 (10.9%) of the carrier mothers were e-Ag-positive compared with 89 (74.8%) who had anti-e-Ag. There was a positive correlation between the titres of HBsAg and the presence of e-Ag. Studies on 49 mother-child pairs revealed that vertical transmission occurred from six of seven carrier mothers (85.7%) who were e-Ag positive compared with two of 32 mothers (6.25%) who were e-Ag negative but had anti-e-Ag. On the basis of these results, the low prevalence of e-Ag in asymptomatic Saudi mothers contrasts markedly with the situation in asymptomatic carrier mothers from the Orient, but its presence, as shown by other studies, is a good predictor of vertical transmission.