Why do we call them ‘baby showers’ and not ‘fetus showers’. Why is it called ‘childbirth’ and not ‘fetusbirth’? When we’re ‘expecting’, what are we expecting?

Why do we call them \'baby showers\' and not \'fetus showers\'. Why is it called \'childbirth\' and not \'fetusbirth\'? When we\'re \'expecting\', what are we expecting?