An additional 54 children delivered to mothers with chronic HBV infection who did not receive LdT treatment during their pregnancy were selected as controls. The children's parents were matched by age and educational level. In addition, a congenital anomalies observation control group included infants born to mothers with chronic HBV infection who did not receive NA treatment during their pregnancy at Beijing Ditan Hospital between January 1, 2010 and December 31, 2010 (n = 2747) and between January 1, 2011 and December 31, 2011 (n = 2567).