Well, in the books the physical differences between Earthers, Martians and Belters are very striking. Due to the lower gravity on Mars, and the even lower gravity on spinning asteroids in the belt; Earthers end up being much shorter than their counterparts with Belters looking very bizarre. I would imagine it would result in them being shorter, and if the gravity is high enough it could completely stunt the baby’s growth in a sort of inverse to what the Belters go through.