Efficacy of antiviral therapy for the prevention of mother-to-child transmission of hepatitis B virus and the risk of postpartum hepatitis flare after discontinuation of antiviral therapy.

The use of nucleos(t)ide analogs (NAs) is recommended for mothers with a high viral load of hepatitis B virus (HBV) during the second or third trimester of pregnancy. However, postpartum hepatitis flares can occur in some cases. We examined the efficacy of NA administration for the prevention of mother-to-child transmission of hepatitis B virus, and evaluated the risk of postpartum hepatitis flares in mothers after NA discontinuation. Nine pregnant women with a high viral load (HBV DNA ≥5.3 log IU/mL) received tenofovir disoproxil fumarate (TDF) at approximately 28 weeks of gestation, and TDF was discontinued at 4-10 weeks after delivery. We evaluated the virological and biochemical parameters in mothers after TDF discontinuation. Hepatitis flares in mothers were defined as alanine transaminase level ≥60 U/L. None of the infants developed any congenital anomaly or acquired HBV infection during infancy. Hepatitis flares occurred within 6 months after TDF discontinuation in five of seven cases, whereas two cases were lost to follow-up. Furthermore, three cases required the resumption of NA use. NA administration was highly effective against mother-to-child-transmission of HBV in pregnant women with high HBV DNA levels. However, hepatitis flares were commonly observed after NA discontinuation in the postpartum period. Patients should be followed up carefully after NA discontinuation, and NA resumption should be considered based on a comprehensive assessment of virological and biochemical parameters.