In the first days post-birth, you're only producing small amounts of colostrum (special milk that protects babies from infection). (romper.com)
A new born baby has a very small stomach; she needs small amount of colostrum. (gomama247.com)
It is possible to start expressing small amounts of colostrum in pregnancy, but should never be considered until you are over 37 weeks (term). (expressing-mama.com)