PERINATAL TRANSMISSION OF HEPATITIS B VIRUS (HBV) INFECTION IN OBAFEMI AWOLOWO UNIVERSITY TEACHING HOSPITALS COMPLEX, ILE-IFE

Abstract

Background: Perinatal transmission of Hepatitis B Virus (HBV) accounts for the majority of
chronic HBV infections worldwide. An assessment of the risk of vertical transmission of HBV in
this environment will help in the development and promotion of strategies to reduce this mode of
transmission, thereby decreasing the global HBV burden.
Objectives: To determine the maternal seroprevalence of HBV, its perinatal transmission rate,
and the maternal characteristics influencing the vertical transmission of HBV infection in
OAUTHC, Ile-Ife.
Method: Seventy-three HBsAg positive pregnant women identified during routine antenatal
screening between September and December 2011 were recruited for this study and followed up
till delivery. At presentation for delivery, each subject’s data was recorded in a study proforma
and 5mls of venous blood was collected. At delivery, a 5ml sample of the baby’s blood was
obtained from the cord.
The sera of each mother and baby pair were analyzed for HBsAg, Hepatitis B e antigen
(HBeAg), hepatitis B e antibody (anti-HBe), hepatitis B surface antibody (anti-HBs) and total
hepatitis B core antibody (anti-HBc) using an immunochromatographic 5-in-1 panel kit to
determine their infectivity status. Quantitative analysis of the HBV DNA levels in the maternal
and neonatal blood samples was done using a PCR based technique. Intrauterine infection was
defined as HBsAg positivity and/or HBV DNA in neonatal blood at delivery.
Data obtained was subjected to statistical analysis using SPSS version 16.0. Proportions
were compared using the Chi-square and Fisher’s exact tests, while logistic and multiple
regression techniques were used to determine the association between maternal characteristics
and rate of perinatal transmission. The confidence level was set at 95% (p<0.05).
Results: Of the 716 pregnant women screened over the four month period, 73 (10.2%) tested
positive for HBsAg. Of these 73 HBsAg positive women, 50 (68.5%) delivered in the study
centre during the period of study. HBsAg was positive in 12 out of the 50 newborns (24%) and
HBV DNA was detectable (>100 copies/mL) in 36 of the 50 newborns (72%). Consequently, the
vertical transmission rate was 72%. High maternal DNA titre was associated with increased
neonatal HBV DNA titre (p<0.001). Parity, maternal age, and mode of delivery were not
associated with risk of intra-uterine transmission.
Conclusion: There is a high prevalence of maternal and intra-uterine HBV infection in Ile-Ife.
Vertical transmission rate is increased in the presence of high maternal viremia. It is however
not influenced by maternal age, parity, mode of delivery or presence of risk factors for HBV.
Mandatory antenatal screening of all pregnant women with appropriate prophylaxis for all
HBsAg positive mothers and their newborns is advocated.

PERINATAL TRANSMISSION OF HEPATITIS B VIRUS (HBV) INFECTION IN OBAFEMI AWOLOWO UNIVERSITY TEACHING HOSPITALS COMPLEX, ILE-IFE