This will probably be argued until the end of time. I disapprove of abortions as a method of birth control, like Caring Parent wrote that the women she knows felt it wasn't the right time. If it's not the right time, please don't allow a pregnancy to happen in the first place. Obviously in the case of rape, that is not possible. In the case of rape or accidental pregnancy (birth control method failed) where the mother is just not prepared mentally to carry a child to term or deal with it afterwards (keep it or give it up) then an early abortion (well before 4 months gestation) would be agreeable, in my humble opinion.
Women (and men) must take responsibility in advance of pregnancy. Just as we try to protect ourselves from AIDS, herpes and other STD's, pregnancy should not be the least of the concerns just because it seems to be the easiest to "cure" at the moment.