I totally get what you mean, but then the real question becomes: why implement the early stages of pregnancy in the first place? Isn't that a waste of coding effort (and of player time) if it cannot lead to anything?
Unfortunately there is a lot of waste in the game. Settings only used for one scene or quest, character's and relationships that aren't pursued, items like clothing (the business suit used in the college) that are only used for one quest and etc.
I suspect the reason is the Dev wanted to fulfill patron request, I would imagine that is the answer for the pregnancy as well, as I'm sure he's probably had multiple request for the content.
The bright side to it all is that there are lot's of assets available for fan remakes. Personally I've always felt like Jane was neglected as a character and that a lot more could have been made out of her friendship with Alex. I hope someone takes on the project someday.