abortion itself, being a personal decision/action, doesn't seek to affect the thoughts and behaviors of other people. perhaps you mean anti-abortion, since that attempts to be positively coercive of others?
Even if we assume that "it's a personal choice" is some kind of natural/god-given/obvious default (which historically it hasn't been), we'd still to work to change the minds of people who think otherwise...
For example, I know many Icelanders are quite proud of how they have 'solved' the problem of Down Syndrome in their country by good prenatal testing. I strongly suspect women in countries like this face tremendous pro-abortion pressure when they consider carrying these children to term and welcoming them into their families.