Importance of maternal and cord blood viremia in pregnant women with chronic hepatitis B virus infection

Background/aimThe spontaneous preterm birth (SPB) rates in a group of HBeAg-negative chronic HBV infected pregnant women without several known risk factors for preterm delivery as well as the mother to infant HBV transmission rates was evaluated. Moreover the role of maternal data during perinatal period as well as the role of HBsAg and/or HBV-DNA presence in cord blood in respect to preterm labour and vertical transmission of the infection was examined.Methods138 consecutive chronic HBV infected pregnant women were haematologically, serologically and virologically evaluated during the perinatal period. 102 women were finally evaluated and fifteen of them (14.7%) exhibited SPB. Overall, 44 infants who had completed the proposed vaccination schedule were evaluated at month 12 of their life.ResultsA significant association between SPB and HBV-DNA presence in cord blood was observed (p = 0.007). HBV-DNA positivity in cord blood was significantly associated with maternal HBV-DNA levels (p = 0.002). The relative risk of HBV-DNA presence in cord blood was 6.43 times higher among women with serum HBV-DNA ≥ 10.000 copies/ml and lymphocyte count < 1500 compared to those with all the other combinations of both parameters (p = 0.001). All infants evaluated at month 12 were HBsAg-negative and exhibited undetectable HBV-DNA levels.ConclusionThe presence of HBV-DNA in cord blood is significantly associated with SPB in chronic HBV infected pregnant women. Maternal or cord blood viremia does not pose an additional risk factor for vertical transmission of HBV infection, in passive–active immunoprotected infants from HBeAg-negative chronic HBV infected mothers.