lt's a typical satisfied smile of a mother to be中的“a mother to a mother to be是不是“a woman who is going to have a baby”?

lt's a typical satisfied smile of a mother to be中的“a mother to
a mother to be是不是“a woman who is going to have a baby”?

你的理解是对的
a mother to be指即将成为妈妈（的人）