Just for reference, have we ever had a canon Jedi who had to leave the Order because of a relationship?
Personally, I don't see any reason to believe Bastila ever got pregnant at all. It seems obvious to me that she had a sister that Revan screwed and knocked up in a completely unrelated set of circumstances.
It also definitely took place before the amnesiac Revan was re-trained during the events of KotOR, but after he lost his memories.
"There is something going on in time and space, and beyond time and space, which, whether we like it or not, spells duty." -Winston Churchill
"For of all sad words of tongue or pen, The saddest are these: 'It might have been!'" -John Whittier
"Apathy is death." -Kreia