1. Many infants born to HBAg-positive mothers do not have detectable antigen in their cord blood (Smithwick and Go,1970
2. The age at which infected infants become HBAgpositive varies, but it is usually before the sixth week of life;Merrill, Dubois; Kohler, 1972, Schweitzer,1974
3. The titre of the maternal antigen correlated well with the likelihood of transmission in Taiwan (Stevens;et al; but not in England (Cossart and Cohen,1975
4. the most important factor recognizable in determining transmission from mother to infant is the activity of the mother's liver disease, but this is difficult to assess during pregnancy because of the physiological alterations in liver function. Many 'healthy' carriers have chronic hepatitis which is only revealed by specific investigation and in at least one larger series;far, So,1975
5. Very little is known about the outlook for infants who acquire hepatitis B in the first few months of life;al., 1970, Marshall; Dudgeon 1972, McCarthy,1973