Background & Aims Fewer data exist on neuro-mental development after fetal exposure to telbivudine. We investigated the developmental consequences of infants from mothers that received telbivudine treatment for chronic hepatitis B (CHB). Methods CHB mothers with high viral load at gestational week 28 were assigned to receive either telbivudine (LdT) or usual care without antiviral therapy, based on the mothers' preference. Their infants were followed for 52 weeks to assess physical and neuro-metal development with Gesell Developmental Schedule tools. Developmental consequences were compared between the two groups. Results Among 258 mothers enrolled, 159 and 99 in the telbivudine-treated and the non-treated group, respectively. The mean duration of telbivudine therapy for the treatment group was 12.31 ± 1.02 weeks. When compared to the control group, infants at the treated-group at the age of 52 weeks had similar neuro-mental development outcomes regarding Gesell Developmental Schedule scores for gross motor (p = 0.55), fine motor (p = 0.31), adaptive (p = 0.10), linguistic (p = 0.97), and personal social (p = 0.52) domains; their physical parameters were also comparable, which included mean height (77.83±3.31 vs. 77.55±3.03 cm; p=0.51) and mean body weight (and 10.59±1.14 vs.10.57±1.19 kg; p=0.89). However, the vertical transmission rates were slightly higher in the control group (3.19% [3/94] vs. 0% [0/150]; p=0.056). Multivariate logistic regression suggested that telbivudine did not associated with negative developmental consequences. Conclusions The developmental consequences of prenatal telbivudine exposure were comparable to those without the exposure in one year observation. We now know that Telbivudine therapy is safe for hepatitis B mothers during pregnancy; ClincialTrials.gov number, NCT02301650. Copyright © 2020 AGA Institute. Published by Elsevier Inc. All rights reserved.