I think it depends. I’m not personally a fan of pregnancy that never ends unless the game’s naturally going to end before it would have happened.
I don’t like egglaying or anything too alien, but monstrous offspring like goblins could become spawned as allies or enemies after a pregnancy debuff for a period in certain games.
If you’re talking human babies, maybe show them breastfeeding the kid on occasion? Or just note the kid’s off screen. Obviously irl a father should be more involved but this is smut.