A thinking, feeling woman should not be expected to give up her health, her body, her physical integrity, suffer lasting complications, for the sake of a fetus. We don't even require that for grown, thinking, feeling people. The fact that pregnancy MAY happen doesn't mean you should willingly suffer it. Just like you may be injured if you drive recklessly, but that doesn't mean you should punish yourself by not getting medical treatment.
So what it basically comes down to is: the woman—her life, her livelihood, her health, her presence and support (physical, economical, emotional) in the live's of others, including her partner/spouse, her family, any other children she might have (and she probably does, because, statistically, most women who have abortions have at least one child already)—is not nearly as important as the life/existence of that fetus to many pro-lifers.
It doesn't matter if a pregnancy will cost her life or livelihood. It doesn't matter if the physical health effects of a pregnancy will keep the woman out of work, put her at risk for losing her job, keep her from being able to take of herself, her other children, or her family. At the end of the day, pro-life views show that they think a fetus as the most important "individual"; it's existence the most important thing to preserve.