Oh man I just realized, this baby is her SECOND attempt at making a curse. Kaya was her first attempt, but was born prematurely via a C-Section. That's why she's still herself, because she wasn't "born" the way that curses need to be born. That's why when Mayumi went to stay in the hospital, she seemed so insistent that she needed to have a natural birth this time. Because THAT'S how the curse is successfully born