I completely get what you're saying, as it would make sense from a life simulation aspect. But my intent behind adding pregnancy was just to satisfy the breeding & pregnancy kinks, which are about the act of impregnation and the transformation of the body from pregnancy, respectively.
Pregnancy will be off by default and something players opt into when starting a new game. The good news is that if the sex update doesn't end up taking me too long, then I'll be able to get started working on the Personality update sooner.