I believe the law of the land should be "Legalized Paternal Surrender", that a man should be able to revoke any parental rights and responsibilities that he has until shortly before she can abort.
Yes, she should have a window of time in which to abort if she doesn't think she can reasonably care for the baby without his help/money.
The idea that a woman should be able to force a man into parenthood but a man should not be able to force a woman into parenthood is blatantly unfair. As feminists love to point out, he chose to have sex, but so did she. We're not talking about rape (though interestingly, even when she rapes him, he is still on the cook for any resulting children).
Of course, once she cannot abort, no, I don't think he should be legally able to back out of it without severe consequences (child support etc).