Yes. I think your statement assumes that women who get pregnant unintentionally would of course want to bear a child, that maternal instinct is the default. But women, like men, may have other things we want to do with our lives.
I've heard at least a hundred women testify in person about their abortions (and of course read zillions more) and the overwhelming feeling is relief. (And when I've had pregnancy scares, simply the existence of legal abortion has been a great relief--not to mention that having abortion as a backup makes sex less tense and therefore more enjoyable.)
The thing is, when you're considering abortion the other option is pregnancy and childbirth, and usually childrearing. It's not like there are a bunch of other possibilities. It's kind of like divorce--once in a while a particular divorce can be kind of a mess emotionally, but overall it's a great relief even for those for whom it's a mess, since the other option is spending the rest of your life with someone you don't want to spend the rest of your life with. So given the options, abortion is the best thing since the overthrow of monarchy. IMHO.
Jenny Brown