Hepatitis B is a potentially serious, but vaccine preventable infection of the liver caused by the hepatitis B virus (HBV) and is the leading cause of liver cancer in the world.
About 1 in 30 people in the world (approximately 300 million) is living with chronic hepatitis B infection. The prevalence of chronic hepatitis B is highest among adults born in Asia and Africa where hepatitis B is highly endemic. In the United States, as many as 1 in 12 non-US born pregnant women from Asia have chronic hepatitis B. Most of them became infected when they were not vaccinated or offered hepatitis B vaccination at birth.
Perinatal transmission of hepatitis B from HBsAg positive mother carries the highest risk for the newborn to develop chronic hepatitis B infection and the risk for liver cancer in adulthood.
PRENATAL HEPATITIS B TEST
The US CDC and US Preventive Services Task Force (USPSTF) recommend all pregnant women have a prenatal hepatitis B surface antigen (HBsAg) screening test for hepatitis B infection in the first 12 weeks of each pregnancy, even if they have been previously tested or vaccinated.
Prenatal or antenatal HBsAg test, or specify in the lab order - HBsAg test for prenatal screening.
CPT code: 87340 or 87341
Obstetric or prenatal panel/profile (includes HBsAg, HIV, rubella, syphilis, ABO and RH blood type, CBC, rubella and syphilis).
GUIDELINES IN MANAGING HBsAg POSITIVE PREGNANT WOMEN
1. COUNSELLING HBsAG POSITIVE WOMAN
Some women may have only become aware of their infection from the prenatal screening test since most of the people living with chronic hepatitis B have experienced no or few symptoms.
Many infected individuals also lack knowledge about hepatitis B transmission and risks.
So, it is important to provide HBsAg positive women with:
linguistically and culturally appropriate education pamphlet and resources about chronic hepatitis B and prevention of mother-to-child prevention (available under resources tab)
Emphasize to the expecting mother the importance of having her newborn receive HBIG and the birth dose of hepatitis B vaccine as soon as possible after birth to prevent the baby from becoming infected, and from the risks of liver cancer and liver disease later in life associated with chronic hepatitis B infection.
Recommend her household, family and sex partner for screening and hepatitis B vaccination if they are not protected.
For culturally and linguistically appropriate informational brochures about hepatitis B, see Resources tab.
2. ORDER BLOOD TESTS TO ASSESS INFECTIVITY AND LIVER INFLAMMATION
Prenatal HBV DNA level. Measures the amount of virus in blood. In pregnant women with HBV DNA level > 200,000 IU/mL, the American Association for the Study of Liver Diseases (AASLD) recommends prophylactic antiviral therapy with tenofovir disoproxil fumarate (TDF) starting at 28-32 weeks of pregnancy until one month after giving birth to further decrease the risk of perinatal transmission. A positive hepatitis B e antigen (HBeAg) test is an indirect measure of increased infectivity in treatment naive patients.
ALT (alanine aminotranferase) level. Regular monitoring of ALT level during pregnancy is important to detect liver inflammation and hepatitis flare that would require antiviral therapy with tenofovir.
3. SEND COPIES OF THE HBsAG POSITIVE LAB REPORT
To the birth hospital to document the woman's positive HBsAg status. The alert should be included in the woman's medical record to remind the hospital /nursery that the infant needs to receive hepatitis B immune globulin (HBIG) in addition to hepatitis B vaccine as soon as possible and within 12 hours after birth.
To the local county health department for case management by Perinatal Hepatitis B Prevention Program and indicate the positive test result is from a pregnant woman if not stated in the copy of the lab report. (Reporting all HBsAg positive cases is required by law in most of the states)
WHEN IS ANTIVIRAL THERAPY INDICATED OR
RECOMMENDED DURING PREGNANCY?
1. The American Association for the Study of Liver Diseases (AASLD) recommends HBsAg positive pregnant women who meet the standard indications for antiviral treatment (ie, if the pregnant woman had cirrhosis or evidence of liver inflammation with ALT level over 50 U/L associated with HBV DNA level > 2,000 IU/mL in HBeAg negative patient or HBV DNA level >20,000 IU/mL in HBeAg positive patient) should be placed on tenofovir disoproxil fumarate (TDF) 0.5mg/tab/day to protect them from liver injury.
2. Women who are already on antiviral therapy for chronic hepatitis B prior to becoming pregnant should be counselled about the risk of hepatitis flare that can cause sickness from liver damage or hepatic decompensation if the treatment is stopped. If the patient was taking entecavir to treat chronic hepatitis B before she became pregnant, she should be switched to tenofovir. (Entecavir is not approved for use in pregnant women)
3. AASLD recommends prophylactic therapy with tenofovir disoproxil fumarate (TDF) 0.5mg/tab/day in women who do not meet the standard indication for antiviral therapy but are highly viremic with HBV DNA level over 200,000 IU/mL. TDF is recommended starting from 28 or 32 weeks of pregnancy until 4 weeks after delivery. After prophylactic TDF is stopped at 4 weeks postpartum, the patient ALT and HBV DNA level should be monitored every 2-3 months for hepatitis flare which occasionally can lead to hepatic decompensation if left untreated. After delivery, HBsAg positive women should resume the standard recommended long-term monitoring tests including blood tests for ALT every 6 months.
AMNIOCENTESIS AND CESAREAN SECTION
Recent studies found amniocenteses was associated with an increased risk of mother-to-child transmission of hepatitis B in pregnant women who are highly viremic with HBV DNA level over 2,000,000 IU/mL. Hence the risk benefit ratio of amniocentesis should be considered in pregnant women with high viral load.
Recent studies have also shown C-section does not reduce the risk of mother-to child transmission of hepatitis B.