A 23-year-old pregnant woman is found to have chronic viral hepatitis B on liver biopsy. The presence of which of the following serologic markers is most likely to increase the risk of vertical transmission of the virus?

Question

A 23-year-old pregnant woman is found to have chronic viral hepatitis B on liver biopsy.  The presence of which of the following serologic markers is most likely to increase the risk of vertical transmission of the virus?

Quizplus · Accepted Answer

Vertical transmission of hepatitis B from pregnant females to the unborn child can occur with active hepatitis B infection. Typically, such transmission takes place during the passage of the fetus through the birth canal, but transplacental infection can also occur. This is especially common in those women who developed acute hepatitis B infection in the third trimester. The presence of HBeAg (a soluble protein that is a marker of viral replication and increased infectivity) in the mother significantly increases the risk of vertical transmission of the virus. Were this woman HBeAg negative, her neonate's risk of infection would be 20%. If she were HBeAg positive, however, her neonate's risk of infection would be 95%. Moreover, should the infant become infected, his chance of progression to chronic hepatitis is 90%. Because of this concern, the newborns of all mothers with active hepatitis B are passively immunized at birth with hepatitis B immune globulin (HBIG), followed by active immunization with recombinant HBV vaccine. (Choice A) HBcAg is not detectable in serum as it is normally sequestrated within the HBsAg coat. (Choice B) HBsAg is the first virological marker detected in the serum after inoculation, preceding both the elevation of serum aminotransferases and the onset of clinical symptoms. It remains detectable during the entire symptomatic phase of acute hepatitis B and suggests infectivity. It is not the most ominous marker in the pregnant woman, however. (Choice D) Anti-HBc appears in the serum shortly after the emergence of HBsAg and remains detectable long after the patient recovers. The IgM fraction signals the acute phase of disease, whereas the IgG fraction signals recovery from the disease. Because IgM anti-HBc is present in the "window period," it is an important tool for diagnosis when HBsAg has been cleared and anti-HBs is not yet detectable. Thus IgM anti-HBc is the most specific marker for diagnosis of acute hepatitis B. (Choice E) Anti-HBe suggests the cessation of active viral replication and low infectivity. (Choice F) Anti-HBsAg IgG appears in the serum after either successful HBV vaccination or the clearance of HBsAg and remains detectable for life. It serves as an indicator of noninfectivity and immunity. However, there is a time lag between the disappearance of HBsAg and the appearance of anti-HBs in the serum, which is termed the "window period." Educational Objective: Vertical transmission of hepatitis B from pregnant females to the unborn child can occur in women with active hepatitis B infection. The presence of HBeAg (a marker of viral replication and increased infectivity) in the mother greatly increases the risk of vertical transmission of the virus. Because of this concern, the newborns of all mothers with active hepatitis B are passively immunized at birth with hepatitis B immune globulin (HBIG), followed by active immunization with recombinant HBV vaccine.

A 23-Year-Old Pregnant Woman Is Found to Have Chronic Viral