Real-world clinical and virological outcomes in a retrospective multiethnic cohort study of 341 untreated and tenofovir disoproxil fumarate-treated chronic hepatitis B pregnant patients in North America.

BACKGROUND There are limited long-term data on outcomes of chronic hepatitis B (CHB) in untreated and tenofovir disoproxil fumarate (TDF)-treated women during pregnancy. AIMS To assess clinical outcomes in a multiethnic cohort of patients during pregnancy and post-partum in a low HBV endemic region. METHODS Retrospective real-world study of women with CHB (treated or untreated with TDF) from 2011 to 2019; data including ALT, HBV DNA, HBeAg and liver stiffness measurement were collected during pregnancy and post-partum. RESULTS In 341 women (446 pregnancies) followed for a median of 33 months (IQR: 26.7-39.5) post-partum, 19% (65/341) received TDF (11 initiated pre-pregnancy, 53 for mother-to-child transmission (MTCT) prevention). During follow-up, 72/341 had subsequent pregnancy, including 18/53 on TDF for MTCT risk, of whom 7/18 were re-treated. In all TDF-treated women, HBV DNA declined but rebounded after TDF withdrawal (median baseline, near birth and early follow-up levels were 7.2, 3.0 and 5.5 log IU/mL respectively [P < 0.01]). In HBeAg+ patients (65/341) ALT flares were more common (P = 0.03), especially for those who stopped TDF post-partum, requiring re-treatment in 21% (11/53). In comparison, 54% (116/215) of untreated women had a post-partum ALT flare; one with fulminant hepatitis underwent transplant 13 months post-partum. HBsAg clearance occurred in 2.6% (9/341, 3/9 HBeAg+, 2/9 TDF treated) at median 30 months (IQR: 23-40) and 37% (24/65) of HBeAg+ patients had HBeAg loss at median 17 months (IQR: 12-26) post-partum. CONCLUSIONS Post-partum ALT flares were common, especially after TDF withdrawal. Overall, 37% achieved HBeAg clearance and 2.9% had HBsAg loss during long-term follow-up.