Really good article on abortion. It's really hard to define the difference between a foetus and a baby. Viability is one - can it survive outside the womb?
Maybe the solution to the time limit should be that the foetus is removed from the woman's womb and the resulting baby is given to people willing to adopt. This (probably HUGE) cost would be covered by an optional baby saving tax.
Happy solution - the people who care pay, the woman has the option to change her mind (and a small scar) and the pope will smile.