Hepatitis B Carriers in Hong Kong: Prevalence and Pregnancy Outcomes

Abstract

Objectives: To determine whether the point prevalence of hepatitis B surface antigen (HBsAg) carriers varies with maternal age, and to assess the impact of hepatitis B virus carrier status on pregnancy and perinatal outcomes.
Methods: A total of 9526 patients who had delivered in Queen Elizabeth Hospital in Hong Kong between 1 October 2010 and 31 December 2011 were included in this retrospective study.
Results: The HBsAg carrier rate was lower in younger maternal age-groups, being 11.3% in women aged ≥43 years and 8.0% in women aged ≥22 to <43 years, and 4.4% in women aged <22 years (p=0.016). Parity was higher among HBsAg carriers (0.70 vs. 0.58, p<0.001). The prevalence of positive HBsAg status was significantly lower in Hong Kong residents compared with non–Hong Kong residents (6.8% vs. 13.3%, p<0.001). There was no significant difference in the point prevalence of major antenatal complications in HBsAg carriers and non-carriers. Among the hepatitis B carriers, the elective Caesarean section rate was higher (13.8% vs. 12.9%, p=0.018), as was the rate of postpartum haemorrhage (4.0% vs. 2.7%, p=0.033). By contrast, the rate of epidural analgesia use was lower (4.4% vs. 6.2%, p=0.045), as was the rate of emergency lower segment Caesarean section (11.6% vs. 15.5%, p=0.018). Moreover, the mean birth weights of babies delivered by hepatitis B carriers were significantly greater (3184.3 g vs. 3144.3 g, p=0.042), but there were no other major differences in perinatal outcomes.
Conclusion: Declining maternal carrier rate of HBsAg in women aged <22 years was observed, probably due to the effects of the universal neonatal vaccination programme implemented since 1998. Carrier status was associated with a higher elective Caesarean section rate and a mildly larger birth weight. Further studies are warranted to elaborate these associations.