The belly scaling while moving through the dungeon is tied to the cum meter. At 200 cum the belly is at 100% scaling, assuming the cumflation feature is turned on in the settings.
As for pregnancy? I don't know. there have been a lot of requests for it, but I'm not too keen on adding it as a game mechanic. If I were to add it to a cinematic it would probably be in a happy ending style game over or something.
Edit: Formatting.
I mean it could be used as a follower mechanic. Higher cum levels increasing odds of pregnancy and you add each encounter to a list and with a for loop pick randomly one of the monsters to be her father. You could even further influence the stats of the monster follower via statue buffs. Due to the nature of the dungeon. The rate at which monsters grow to adulthood is faster, so giving birth takes maybe like 2 turns and monster grows to adulthood in 4 turns.
