A 28-year-old woman is evaluated at 28 weeks' gestation. This is her first pregnancy. She has chronic hepatitis B virus (HBV) infection acquired through vertical transmission. The patient reports feeling well. Her only medication is a prenatal vitamin.
On physical examination, vital signs are normal. The uterus is enlarged, consistent with 28-week intrauterine gestation. No stigmata of chronic liver disease are noted.
Laboratory studies are positive for hepatitis B surface antigen and hepatitis B e antigen. The HBV DNA level is 300,000 IU/mL. The results of other studies, including alanine aminotransferase, aspartate aminotransferase, and total bilirubin levels, are within normal limits.
Which of the following is the most appropriate next step in management?
A. Cesarean delivery at term
B. HBV DNA measurement in 3 months
C. Pegylated interferon
MKSAP Answer and Critique
The correct answer is D. Tenofovir. This content is available to MKSAP 18 subscribers as Question 30 in the Gastroenterology and Hepatology section. More information about MKSAP is available online.
Tenofovir is the most appropriate next step in management of this patient, with the goal of preventing vertical transmission of hepatitis B virus (HBV) infection from mother to child during the course of delivery. Guidelines recommend treatment with lamivudine, telbivudine, or tenofovir for the prevention of vertical transmission in pregnant women who have HBV DNA levels greater than 200,000 IU/mL at 24 to 28 weeks' gestation. There are no head-to-head data comparing these regimens, but tenofovir is preferred over telbivudine and lamivudine due to lower rates of resistance. Tenofovir and telbivudine are the only FDA pregnancy category B agents. Lamivudine and other oral drugs used to treat HBV are category C agents, though there are reasonable data on the safety of lamivudine use in pregnancy in the HIV population. Only a few patients will become hepatitis B surface antigen–negative with treatment; therefore, cure of HBV infection is an unrealistic goal for most chronically infected patients.
There are no data suggesting that cesarean delivery is effective at preventing vertical transmission of HBV. All babies born to mothers with chronic HBV infection should receive active HBV vaccination and passive immunization (HBV immune globulin). The risk for developing chronic HBV infection is high (90%) in newborns who acquire HBV.
Because the patient's HBV DNA level is high enough (>200,000 IU/mL) to warrant treatment to prevent vertical transmission of HBV, measuring her HBV DNA level again in 3 months would not be appropriate without first instituting treatment.
Pegylated interferon is not considered safe in pregnancy and, therefore, would be an inappropriate choice for this patient. Pegylated interferon can be used to treat HBV infection in patients with high alanine aminotransferase levels, low HBV DNA levels, and without cirrhosis. Candidates for interferon have a desire for finite therapy, do not have cirrhosis, are not pregnant, and do not have significant psychiatric disease, cardiac disease, seizure disorder, cytopenia, or autoimmune disease.
- Pregnant women who have hepatitis B virus DNA levels greater than 200,000 IU/mL at 24 to 28 weeks' gestation should be treated with tenofovir to prevent vertical transmission during delivery.