a note about stretchmarks:

i'm not sure if it is genetic or how it goes (my mother still blames me for hers to this day, but i did not get any myself during my own pregnancy?) but a nice exfoliant can't hurt..
gently sugar scrubbing with a nourishing oil every day..

or even more gentle is lactic acid.. so, milk baths, yogurt masks..

i hope your partner feels very beautiful through the stages of her pregnancy and thereafter :)