Prevalence of hepatitis B virus infection among pregnant women attending prenatal care at Mae Sai Hospital in the border regions of northern Thailand

Background: Hepatitis B virus (HBV) infection is a major public health problem worldwide and a major cause of liver diseases. Pregnant women with HBV infection are reservoir for the virus to transmit it to their child. Most infants (90%) who are infected with HBV will develop chronic infection and 25% will die prematurely from liver cancer or cirrhosis. Objectives: To assess the prevalence of HBV infection among pregnant women attending prenatal care at Mae Sai Hospital, a border region in Northern Thailand. Materials and methods: This retrospective cross-sectional research study collected data from the hospital records database between January 2019 and September 2023. All pregnant women were tested for serum HBsAg marker by the STANDARD Q HBsAg Test. Statistical analyses were conducted using IBM SPSS version 29.0, with logistic regression used to detect the associations between variables at a significance level of p<0.05. Results: The study population comprised 2962 pregnant women, with 29.98% Thai and 70.02% non-Thai divided into Burmese (48.12%) and other ethnic groups (51.88%). The overall prevalence rate of HBV infection among pregnant women was 4.9% (95%CI=4.1-5.7). The HBV prevalence rates of Thai pregnant women and non-Thai pregnant women were 2.9% (95%CI=1.8-4.2) and 5.7% (95%CI=4.7-6.9), respectively. Two variables (nationality and year of birth) were associated with hepatitis B infection. Non-Thai pregnant women had a 2-fold (95%CI=1.998-3.161, p=0.003) greater chance of HBV infection than Thai pregnant women, while Thai pregnant women born before the implementation of the national vaccination program had a 4.2-fold (95%CI=1.757-10.037, p=0.004) greater chance of HBV infection than those born after the program implementation. Conclusion: This study found a lower prevalence of hepatitis B virus infection in pregnant women compared to previous studies. Only born vaccination was an associated factor with hepatitis B infection. It is essential to raise awareness, promote preventive measures, and implement screening before pregnant planning or receiving HBV vaccine to stop the infection during pregnancy leading to stop transmitting of hepatitis B to their children.