i am in no way an expert in this, i had my baby in hospital but am thinking poss next time i might try for a home birth. but i don't think midwifes will let you give birth in the bathtub as they don't have good enough access to be bal to help you.
i may be wrong but im sure someone who knows much more than me will reply with all the facts.
i did use the bath breifly in my labour but wasn't a fan, i was too scared i wouldn't be able to get back out!!!
good luck