I finished 0.37 and Yuki was pregnant...but in 0.38 doesn´t...Most likely you getting Julia's appearing everytime you enter Jason's room, that's preventing Kelly from surprising you in Jason's room, starting of the pregnancy of Yuki.
What to do
Download 0.37 from the OP play that version, complete the 0.37 section of the walkthrough, making sure to have Janice's bed as the default, save then start 0.38.