That's debatable.
Yeah, that's part of it. But there's also the time frame CH plays in, which is just over a week so far. There are of course ways around that, like time skips or having the ending(s) play in a more distant future, but yeah.
The one big reason why I won't add any pregnancy to CH, though, is that I simply dislike it myself. Pregnancy content is very low on the list of things I enjoy and I would hate to have to create scenes like that, which would inevitably lead to them being of lower quality than other scenes with content I do enjoy. :)