Mothers and pregnant women in contemporary western societies are at the centre of a web of expert and lay discourses concerning the ways they should promote and protect the health and development of their foetuses and infants. This article reports the findings from an Australian study involving interviews with 60 mothers. The findings explore in detail four topics discussed in the interviews related to pregnancy and caring for young infants: disciplining the pregnant body; promoting infants' health; immunisation; and promoting infants' development. Itis concluded that the mothers were highly aware of their responsibilities in protecting their foetuses and infants from harm and promoting their health and development. They conceptualised the infant body as highly vulnerable and requiring protection from contamination. They therefore generally supported the idea of vaccination as a way of protecting their babies' immature immune systems, but were also often ambivalent about it. The mothers were aware of the judgemental attitudes of others, including other mothers, towards their caring efforts and attempted to conform to the ideal of the 'good mother'. The emotional dimensions of caring for infants and protecting their health are discussed in relation to the voluntary participation of mothers in conforming to societal expectations.