The game takes place over the course of a year. There's not enough time for pregnancy to really happen unless it sets in before half way, and story wise it makes most sense as a end of route kind of thing as a final escalation.
Pregnancy as part of an ending (and/or an impregnation animation during the game itself but without visible progression beyond that) are both things I am PLENTY happy with lmao. Are either possible or nah?