Overlooked the request for elaborating on the 'acceptable'...
I believe that even when someone feels that she got stuck with the baby against her will AND is not willing or able to overcome that severe negative association she will never be able to develop into a loving, caring mother... the child in question has extremely poor perspectives toward a childhood which forms a good support for his/her further life. Ergo, knowingly introducing a child into an environment where it is unwanted, unloved, not cared for and unsupported is in my opinion not desirable, even to the extent that it could justify an abortion.
That does obviously not reflect your interpretation of 'not acceptable', but I am sure that there are situations that do (a seropositive junkie who's expecting). More importantly, it underlines that any objective, reasonable person could never regard an abortion for this reason similar to that of keeping ones esthetics on par.
