I don't think it's important how developed a fetus is. A newly formed fetus is very able and usually going to develop into a baby person. Sex is an act that requires a lot of responsibility, because sex is first and foremost a way to procreate. That's why animals do it. That's why humans haven't died out. Granted, many and most humans have sex for pleasure (as do dolphins, fun fact), but that doesn't mean people shouldn't be aware of the consequences: STDs, pregnancy, etc.
A method for preventing pregnancy that is natural, church-approved and 99% effective is known as "Natural Family Planning". For those considering sexual intercourse, I strongly suggest learning about NFP. I think a lack of education may be a reason why artificial abortion exists in the first place. That, and being irresponsible.
I don't have an answer for pregnancy caused by rape.