Drug abuse is a primary contributor to birth defects in China.22 The congenital abnormality rates for infants born to mothers without or with HBV infection are 5.1–6.3% and 7.2–10%, respectively.18, 19 and 20 An overall rate of congenital abnormalities of 3.8% (2/53) has been reported in infants whose mothers took LdT for chronic HBV throughout pregnancy.14 In our study, none of the infants had abnormal hearing, congenital phenylketonuria, or hypothyroidism in follow-up periods lasting more than 12 months and some up to 48 months. Congenital dysplasia was detected in three cases within the neonatal period, resulting in a congenital abnormality rate of 5.55%, which is similar to that of women without or with HBV infection in previous reports.18, 19 and 20 In addition, there were no significant differences in congenital dysplasia between children exposed to LdT and the controls. Hemangioma, abnormal lingual frenulum, and vaginal canal leak were found in three of our infants, all in the early-pregnancy treatment group. One patient in the late-pregnancy treatment group had delayed language abilities without a nervous disorder. No other genetic metabolic diseases or congenital defects were found. Therefore, our observations do not support a relationship between LdT exposure and birth defects or genetic disease; however, additional large-sample studies are warranted, especially in children exposed to LdT throughout pregnancy.