I'm ranty so apologies in advance.
I'm 38 weeks pregnant with DC4 it's not been an easy pregnancy and I have been in and out of hospital for the last 10 weeks with issues.
I last saw my mum 8 weeks ago she lives 5 mins away but her last visit didn't go to well as she is a bit toxic and started on about (in front of DCs) how her other GC is her favorite because he has SN and how my sis needs more help because she is a more likeable person and not a horrible liar like me 
She was also very rude about my DP and referring to my stbxh as her fav son in law (who I split with due to DV).
She ignored DPs invitation to my baby shower, which was a surprise for me and although not everyones cup of tea a simple yes or no eould have sufficed but she ignored the invite completely.
She hasn't bothered with my DCs at all even their birthdays were passed by with a card passed on by my Sdad (who split with her) and they haven't seen her since her last visit.
Anyway I digress I have decided not to tell her when DC4 is born and if she was interested she would call or text herself and ask either that or she will end up seeing me in town with the pram, she doesn't even know what DC4 is going to be named as she hasn't been in contact, however Sdad thinks IABU and she at least deserves to be told.
I have already told Sdad that if he tells her its fine (He is having DCs for a holiday around due date) but I don't see why I should make the effort when she hasn't AIBU?
As a side note I have text her since I last saw her as she was ill for a couple of days but nothing since from her.