Sero-prevalence of hepatitis B virus and associated factors among pregnant women in Gambella hospital, South Western Ethiopia: facility based cross-sectional study

Hepatitis B virus is a hepatotropic deoxyribonucleic acid (DNA) virus which occurs through immune-mediated killing of infected liver cells. It is also recognized as oncogenic virus that can cause a higher risk of developing hepatocellular carcinoma [1]. It is 50–100 times more infectious than HIV [2]. The infection with the hepatitis B virus can be lifelong, causing cirrhosis (liver scarring), liver cancer, liver failure, and death. It can be acute (with discrete onset of symptoms and jaundice or elevated serum ALT > 100 IU/L or chronic with no symptoms. The rate for chronicity is approximately 5% in adult infections, but it reaches 90% in neonatal infections [3, 4].

More than 300 million people have chronic liver infections globally and about 600,000 people die annually from acute or chronic complications of hepatitis B infection. Hepatitis B prevalence is highest in sub-Saharan Africa and East Asia, where between 5 and 10% of the adult population is chronically infected [5, 6].

HBV places a heavy burden on the health care system because of the costs of treatment of liver failure and chronic liver disease (easily reaching up to hundreds of thousands of dollars per person). Chronic viral hepatitis also results in loss of productivity [5].

In countries where HBV is highly endemic (HBsAg prevalence rate of 8% or higher), most infections occur during infancy and early childhood [7]. Recent studies conducted in Ethiopia showed moderate endemicity (3–7.8%) of HBV among pregnant women [8, 9].

Previous studies conducted in different parts of Ethiopia showed that history of use of sharp materials, having multiple sexual partners, ear pricing, abortion, Place of delivery, Genital mutilation, history of tooth extraction cesarean section and tattoo for cosmetics were associated factors for HBs Ag sero-positivity [8, 10‐13].

HBV infection during pregnancy is closely related to high risks of maternal complications including: pre-eclampsia, placenta praevia, preterm delivery, placental separation, ante partum haemorrhage, preterm labour, increased incidence of intraventricular haemorrhage, gestational diabetes mellitus and mortality with a high rate of vertical transmission leading to fetal and neonatal hepatitis [14]. Transmission from mother to infant takes place in uterine, during delivery, and after birth. Children born to HBsAg+ and hepatitis e antigen (HBeAg+) mothers have 70–90% chance of prenatal acquisition of HBV infection and over 85–90% of them will eventually become chronic carriers of the disease. Chronic carriers of HBV are main reservoirs for continued transmission of HBV and have a higher risk of hepatocellular carcinoma and liver cirrhosis [1, 15, 16].

Since HBV infected pregnant women are at risk of infecting their babies, knowing magnitude of HBV status and its risk factors in the area is very important. However, there is paucity of information on sero- prevalence of HBV and associated factors among pregnant women at Gambella town. Therefore, the aim of this study is to give deep insight on the magnitude of HBV and its associated factors among pregnant women in anti natal care (ANC) clinic of Gambella hospital.

The result of this study showed that the prevalence of HBsAg among pregnant women attending antenatal care was 7.9%. According to WHO criteria which classifies endemicity of HBV infection; low endemicity areas (less than 2% sero positive), intermediate endemicity area (2% to 7% sero positive) and high endemicity area (≥8% sero positive), the result showed intermediate endemicity area [18]. The result of this study is in accordance with the hospital based cross-sectional study done at Hawassa University Teaching and Referral Hospital 7.8% and Seroprevalence of hepatitis B surface antigen among pregnant women attending the Hospital for Women & Children in Koutiala, Mali 8% [9, 19]. The result is also almost concordant with the findings found from the study areas of Congo 8.7% [20] and Addis Ababa 6% [17]. Among various risk factors abortion, occupation and multiple sexual partner were statistically significant. However, lower and higher prevalence of HBV infection was assessed in similar study populations in different areas of the world. Areas with high magnitude of HBsAg sero-prevalence include 16.5 % in Nigeria and 10.2% in Cameroon [7, 21]. Some of the areas in which low prevalence of HBV infection detected were 3.1% in Rwanda ,4.3% in Arba Minch and 4.9% in Dessie [9, 12, 22]. Even if the study design is similar, Variations in the prevalence of HBV infection within different parts of the world may be due to differences in the methods used for screening for HBsAg, sample size difference, local government attention for the virus, and cultural and behavioral differences regarding possible risk factors of HBV infection.With regard to socio-demographic status of study participants, high prevalence 7 (9.72%) of HBV infection was observed among pregnant women of age 16 to 20 years and low prevalence observed among those with age of 21 and above years, but the difference was not statistically significant. The observed high prevalence of HBV positivity among younger age group could be defined with the high probability of exposure for high risk health behavior but this is contrasted with other studies because high prevalence of HBV infection was found on the study subjects of age greeter than 20 years [11, 22, 23]. Concerning levels of education, it was noted that high prevalence 12 (15%) of HBV infection was detected among pregnant women who had primary educational [1‐8] status and the low prevalence 1 (5.26%) of HBV infection among those who cannot read and write may be due to their low number in the study. Even if it was not statistically significant (p-value> 0.05) which made it different from other study reports conducted in Dessie [10], generally the prevalence of HBV infection decreased with increasing levels of education which is in line with other studies conducted in different areas [8, 9]. Although there is no statistical significant difference with residence, pregnant women who were living in urban area had more prevalence19 (7.95%) of HBV infection than those women living in rural which is in line with other study [10, 11]. This may be due to urban women could be engaged in risky life style practices. Based on their occupation, pregnant Women who were unemployed had eight times more likely to be sero-positive for HBV infection than employed. This may be due to that employed pregnant women have good awareness about HBV infection. But this result is in contrast to other results reported from Addis Ababa and Hawassa [8, 9].

According to this study, the prevalence of HBV infection was significantly higher among pregnant women who had history of abortion. The odd of having HBV infection among women with abortion history almost four times higher compared with those who had not abortion history. It is known that, multiple sexual practices may cause unplanned pregnancy which may result abortion and increase the risk of HBV infection if such partners are infected. Accordingly, contaminated instruments used during abortion procedure might increase the probability of acquiring HBV infection. This is similar with a study result reported from Nigeria, Arba Minch, Debre-Tabor and Addis Ababa [7, 12, 17, 24]. When previous place of delivery considered, pregnant women who delivered at home had 13 (11.71%) sero-prevalence of HBV infection while those who delivered at hospital had 3 (6.97%) sero-prevalence. The possible reason may be unsafe delivery practice at home. This is in agreement with a study report from other area of Ethiopia [9]. Except abortion, medical related risk factors like blood transfusion, surgical procedures, place of previous birth and hospital admission were not associated with seropositivity for HBsAg in this study (p-value > 0.05). This may be due to the use of standard procedures and disinfected instruments by health professionals. The result is in agreement with previous study conducted at Hawassa, Dessie and Congo [9, 10, 20]. But hospital admission and surgical procedures were statistically significant with high HBsAg sero-prevalence on a studies conducted in Shashemene [25] and Addis Ababa [17] respectively.

Concerning to behavioral and cultural risk factors, pregnant women who had multiple sexual partner had about 17 times higher risk of being sero-positive for HBV infection than pregnant women who had not history of multiple sexual partner. The significant association of having multiple sexual partner with HBV infection was also reported by other investigators [10, 12]. In this study risk factors like tattooing, piercing, genital mutilation and human bites were not associated with seropositivity of HBsAg (p-value > 0.05). This is similar with a previous study conducted in Addis Ababa and Hawassa [8, 9],on the other hand, another studies conducted in Debretabor and Nigeria (Osogbo) showed that, in contrast to this study body tattooing was associated with prevalence of HBV infection [7, 13, 24]. This variation may be due to cultural practice differences and different materials used during tattooing.

According to this study, only Sharing of earrings, razors and tooth brush and splash of body fluids were significant during bivariate analysis but in the multivariate analysis none of these accidental risk factors assed were associated with prevalence of HBV infection. Among these risk factors history of sharp injury was statistically significant during a study conducted in Debretabor [24].

Unless preventive measures through vaccination are taken to tackle the risk of transmission, the unborn babies are at a higher risk of contracting HBV infection. The infection was significantly higher among pregnant mothers who had aborted previously and had history of sex with multiple sexual partners. In this study, due to lack of laboratory setup, markers of HBV like HBeAg, HBV-DNA were not detected. Therefore, the major limitation of the study was the new infection of HBV in blood and its active period status not included.

This study showed that sero-prevalence of HBV infection among pregnant women in Gambella hospital intermediate endemicity. Abortion, occupation and multiple sexual partners significantly associated with HBV infection among pregnant women. Therefore, to halt spread of the virus, health education on modes of transmission like having multiple sexual partners and abortion should be considered. In addition to this, routine screening and immunization of all pregnant women and their infants should be continued in the antenatal and postnatal programs in health facilities.