Objective: To explore the risk factors and the rate of HBV vertical transmission from HBsAg-positive couple to their infant.
Methods: 46 families who had antenatal examination at Fujian Provincial Maternal and Child Health Hospital during August 2010 and November 2011 were chosen as research object. Cord blood was sampled after delivery for HBVM and HBV-DNA quantification. Those with HBV-DNA load ≥ 5 × 10(2) copies/ml were involved in the case group while those having < 5 × 10(2) copies/ml were chosen as controls.
Results: The average positive rate of neonatal cord blood HBV-DNA was 45.7% (21/46), while the positive rates of cord blood HBsAg and HBeAg were 34.8% (16/46) and 23.9% (11/46) respectively. The positive rates of maternal serum HBV-DNA and paternal serum HBV-DNA were 52.2% (24/46) and 69.6% (32/46) respectively, with the positive rate of couple serum HBeAg as 39.1% (18/46) and 32.6% (15/46) respectively. Results from univariate analysis showed that hepatitis B surface markers, serum HBeAg-positive, serum HBV-DNA positive, and serum HBV-DNA load of the couples were risk factors to the HBV vertical transmission (χ(2) = 8.731, 8.414, 8.932, 9.663, 10.823, 3.962, 13.638, 36.501; P < 0.05). Data from the multivariate analysis showed that maternal serum HBV-DNA positive and paternal serum HBV-DNA load were risk factors to the HBV vertical transmission[OR = 17.6 (1.3 - 238.4) ; OR = 3.5 (1.6-7.6)]. Serum HBV-DNA loads of the couples were positively correlated with the cord blood HBV-DNA load, while the load levels of the couple's serum HBV-DNA were higher than cord blood HBV-DNA. There appeared dose-response relationship between couple's serum HBV-DNA load level and the cord blood HBV-DNA load level.
Results: from the analysis of ROC curve showed that both maternal serum HBV-DNA load level (10(3) copies/ml) and paternal serum HBV-DNA load level (10(4) copies/ml) were demarcation points to better forecast the occurrence of vertical transmission of HBV, because there showed higher sensitivity and specificity for the forecasting process. Neonatal outcomes showed no significant difference between the case group and the control group. The negative conversion rate became 15.0% (3/20) when the HBV-DNA positive infants were followed up for 7 months.
Conclusion: Both maternal serum HBV-DNA positive and paternal serum HBV-DNA load were risk factors of HBV vertical transmission. When the maternal serum HBV-DNA load appeared > 10(3) copies/ml and paternal serum HBV-DNA load > 10(4) copies/ml, the rate of HBV vertical transmission would increase.