i think, if you like your idea, stick with it. get a few second opinions and stuff though... other art staff, teachers from other schools, if you know any practising artists etc...
but the birth thing sounds really cool + unique. if you think about it, there will probably be a fair few other still lives (in photography or painting/drawing, whatever), but how may other people do works around the process of birth?
and plenty of people do personal stuff. firstly there's frida kahlo, every man and his dog studies her in art at one time or another. everything she did related to her life. and if you look at old artexpress catalogues, there's always at least one person who's done a series of images of their friends/teachers, or stuff relating to them.
if the only reason your teacher doesn't like them is because they're 'too personal', i don't think that's really a valid reason.
i think go with the birth one, really. but then you risk a low internal mark, cos your teacher apparently doesn't like them... also, perhaps, if you have a really good reason for including the actual birth photos (it'd better be pretty tight though, you couldn't just make something up), you could include those too.
nothing wrong with a bit of controversy (eg. Ron Mueck, Dead Dad, 1996; Marc Quinn, Self, 1991; Marcus Harvey, Myra, 1995, Mat Collishaw, Bullet Hole, 1988, and pretty much anything by Jake and Dinos Chapman (Zygotic Acceleration, Biogenetic Desublimated Libidinal Model (Enlarged x 1000), 1995; Great Deeds Against The Dead, 1994, Tragic Anatomies, 1996, etc...), or Damien Hirst (This Little Piggy Stayed Home, 1996; Some Comfort Gained In The Acceptance Of the Inherent Lies In Everything, 1996)... alot of these works are pretty graphic/violent/disturbing/controvertial, but they're still pretty famous.