I can said if mother are better, there was no difference for me after my ex got babies and in the business it is happened rarely I shoot again a girl after she gave birth. What I can said is for some girls the pussy become much larger after a child but for some girls if they got an episiotomy ( cut of the vagina skin to help the baby to come out ) then in some case they can have some sequels which change their feeling when doing sex.
But mostly the body is the main change after birth, breast are different and body skin not same compact , less firm !

Concerning pregnant, I love them but I refuse to shoot porn with women waiting a baby ...
But in Private of course no blem, I love the curves of pregnancy !!!

PW