Antiviral Therapy for Chronic Hepatitis B in Pregnancy
Antiviral Therapy for Chronic Hepatitis B in Pregnancy
The management of chronic hepatitis B (CHB) during pregnancy remains a challenge and involves various aspects of maternal-fetal care. Despite the standard immunoprophylaxis, a significant portion of infants born to highly viremic mothers remain infected with hepatitis B virus (HBV). Emerging data suggest that antiviral therapy in the third trimester can prevent immunoprophylaxis failure. To minimize fetal exposure to antiviral agents, antiviral therapy during pregnancy should be reserved for mothers with advanced disease or who are at risk for hepatic decompensation. Current safety data suggest that lamivudine, telbivudine, or tenofovir may be used during pregnancy. However, the timing in initiating antiviral therapy requires careful assessment of risks and benefit. The authors provide a systematic review of the features of HBV during pregnancy, risk factors for vertical transmission, and evidence-based data on antiviral use during pregnancy. They propose an algorithm to assess the need of antiviral treatment and monitor mothers with CHB.
It is estimated that two billion people worldwide have been infected with hepatitis B virus (HBV) with more than 350 million with chronic infection. Those with chronic hepatitis B (CHB) have up to a 15 to 40% risk of developing cirrhosis and hepatocellular carcinoma in their lifetime. In Africa and Asia, 8 to 10% of the adult population is chronically infected with HBV, most having been infected during childhood. Up to 50% of new cases of HBV infection are due to vertical transmission. In countries of low endemicity defined by HBV surface antigen (HBsAg) prevalence < 2%, such as the United States and northern or western Europe, the majority of new infections occur among adolescents and adults. These infections are attributable to high-risk sexual activity and injection-drug-use exposures. However, with immigration of individuals from high-risk geographic areas into areas of low risk, prevalence of HBV infection is expected to increase in low prevalence countries, particularly among certain foreign-born groups.
Current indications for the treatment of CHB are based on the disease stage determined by HBV DNA level, serologic status, and evidence of liver injury. Most patients receive treatment because they are in the immune-active phase, have advanced fibrosis/cirrhosis, or have multiple risk factors for liver cancer. The current therapeutic armamentarium for CHB involves oral nucleos(t)ide analogues and pegylated interferon (PEG IFN). Only tenofovir (TDF) and entecavir (ETV) are recommended as first-line oral antiviral therapies. Lamivudine (LAM) and telbivudine (LdT), despite their safety profiles, have high rates of resistance that can result in cross resistance with other oral therapies. Adefovir (ADF) has only moderate antiviral activity with increased rates of resistance and nephrotoxicity with long-term use.
The management of CHB during pregnancy remains a challenge with unique issues that involve various aspects of care for both the mother and fetus. Special considerations include the effect of HBV on maternal and fetal health, effects of pregnancy on the course of HBV infection, antiviral treatment during pregnancy for maternal liver disease, and the prevention of perinatal transmission. Here we provide a systematic review on these issues with a focus on the safety and potential benefit of antiviral therapy during pregnancy.
Abstract and Introduction
Abstract
The management of chronic hepatitis B (CHB) during pregnancy remains a challenge and involves various aspects of maternal-fetal care. Despite the standard immunoprophylaxis, a significant portion of infants born to highly viremic mothers remain infected with hepatitis B virus (HBV). Emerging data suggest that antiviral therapy in the third trimester can prevent immunoprophylaxis failure. To minimize fetal exposure to antiviral agents, antiviral therapy during pregnancy should be reserved for mothers with advanced disease or who are at risk for hepatic decompensation. Current safety data suggest that lamivudine, telbivudine, or tenofovir may be used during pregnancy. However, the timing in initiating antiviral therapy requires careful assessment of risks and benefit. The authors provide a systematic review of the features of HBV during pregnancy, risk factors for vertical transmission, and evidence-based data on antiviral use during pregnancy. They propose an algorithm to assess the need of antiviral treatment and monitor mothers with CHB.
Introduction
It is estimated that two billion people worldwide have been infected with hepatitis B virus (HBV) with more than 350 million with chronic infection. Those with chronic hepatitis B (CHB) have up to a 15 to 40% risk of developing cirrhosis and hepatocellular carcinoma in their lifetime. In Africa and Asia, 8 to 10% of the adult population is chronically infected with HBV, most having been infected during childhood. Up to 50% of new cases of HBV infection are due to vertical transmission. In countries of low endemicity defined by HBV surface antigen (HBsAg) prevalence < 2%, such as the United States and northern or western Europe, the majority of new infections occur among adolescents and adults. These infections are attributable to high-risk sexual activity and injection-drug-use exposures. However, with immigration of individuals from high-risk geographic areas into areas of low risk, prevalence of HBV infection is expected to increase in low prevalence countries, particularly among certain foreign-born groups.
Current indications for the treatment of CHB are based on the disease stage determined by HBV DNA level, serologic status, and evidence of liver injury. Most patients receive treatment because they are in the immune-active phase, have advanced fibrosis/cirrhosis, or have multiple risk factors for liver cancer. The current therapeutic armamentarium for CHB involves oral nucleos(t)ide analogues and pegylated interferon (PEG IFN). Only tenofovir (TDF) and entecavir (ETV) are recommended as first-line oral antiviral therapies. Lamivudine (LAM) and telbivudine (LdT), despite their safety profiles, have high rates of resistance that can result in cross resistance with other oral therapies. Adefovir (ADF) has only moderate antiviral activity with increased rates of resistance and nephrotoxicity with long-term use.
The management of CHB during pregnancy remains a challenge with unique issues that involve various aspects of care for both the mother and fetus. Special considerations include the effect of HBV on maternal and fetal health, effects of pregnancy on the course of HBV infection, antiviral treatment during pregnancy for maternal liver disease, and the prevention of perinatal transmission. Here we provide a systematic review on these issues with a focus on the safety and potential benefit of antiviral therapy during pregnancy.
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