Hepatitis B virus (HBV) is a small DNA virus that contains three principal antigens: 1) hepatitis B surface antigen (HBsAg), 2) hepatitis B core antigen, and 3) hepatitis B e antigen (HBeAg). People acutely infected with HBV may be asymptomatic or symptomatic. Among people with symptomatic HBV infection, the spectrum of signs and symptoms is varied and includes subacute illness with nonspecific symptoms (eg, anorexia, nausea, or malaise), clinical hepatitis with jaundice, or fulminant hepatitis. Transmission of HBV occurs through contact with infected blood or bodily fluids (ie, semen, cervical secretions, and saliva).
Perinatal transmission of HBV infection is highly efficient and generally occurs from exposure to maternal blood during labor and delivery. If appropriate and timely treatment is not instituted, perinatal infection occurs in 70–90% of infants born to mothers who are both HBsAG positive and HBeAg positive. Transplacental passage of HBV is rare. More than 90% of infants who are infected perinatally will develop chronic HBV infection.* In 2012, a total of 2,895 cases of acute hepatitis B were reported nationwide to CDC. It is important to test the hepatitis B status of pregnant women, as mother-baby transmission can be prevented if the mother’s HBV status is known at the time of delivery.
*Source: American Academy of Pediatrics, American College of Obstetricians and Gynecologists. Guidelines for perinatal care. 7th ed. Elk Grove Village (IL): AAP; Washington, DC: ACOG; 2012
Chronic hepatitis B infection is a serious, vaccine-preventable illness that is a major cause of liver failure, liver cancer and premature death in the United States. Identifying HBsAg-positive (hepatitis B infected) pregnant women and administering timely post-exposure prophylaxis for their infants is crucial to prevention of perinatal hepatitis B infection and chronic hepatitis in infancy.
HBsAg-positive tests are reportable to public health in all states, but pregnancy status is rarely reported. To address this issue, the Centers for Disease Control and Prevention (CDC) and partners from health departments, commercial laboratories, the American College of Obstetricians and Gynecologists (ACOG) and other professional organizations have worked together to include pregnancy status in laboratory test reports sent to health departments. These efforts were guided by recommendations of the Council of State and Territorial Epidemiologists (CSTE) to improve identification of HBsAg-positive pregnant women.
Four major commercial laboratories are participating in this effort: ARUP Laboratories, LabCorp, Mayo Medical Laboratories, and Quest Diagnostics. Each laboratory now offers designated HBsAg tests for pregnant women as a standalone assay and/or as part of a prenatal/obstetric panel to facilitate reporting HBsAg-positive women to health departments. A summary of the available prenatal HBsAg tests can be found in the table below.
When ordering an HBsAg screening test for a pregnant or postpartum patient from ARUP Laboratories, LabCorp, Mayo Medical Laboratories, or Quest Diagnostics, ACOG recommends you use a test designated as "Prenatal". The success of timely identification and confirmatory testing for HBsAg-positive pregnant women is dependent on physician and hospital uptake of the designated prenatal HBsAg tests ordered from these laboratories.
DISCLAIMERS: CDC and ACOG do not endorse the use of one laboratory or test over another. Healthcare providers are encouraged to use prenatal HBsAg tests when available for pregnant women rather than tests that are non-specific for pregnant or postpartum women. Laboratories reserve the right to add, modify, or stop performing tests at any time—providers should review any test notifications from laboratories for changes.
Read the ACOG Rounds article about the Algorithm, "ACOG Endorses New Guidance and Algorithm for Prenatal HBsAg Tests: The Importance of Screening Pregnant Women for Hepatitis B Infection."