In Nightfall (book 5) it's revealed that she's pregnant with Tyler Smallwood's unborn twins so I guess it was between book 4 "Dark Reunion" and libros 5 "Nightfall"....
in the end of the 5th book, she was whining that she needed a husband o a fiancee. cause tyler skipped out on her. then she dicho that matt raped her in the 7th. she wasnt mentioned in the 8th and 9th, so we don't know if she's had her "puppies" yet