Being raised Catholic, I was taught that abortion (and contraception and premarital sex) and the death penalty are wrong. I still think the death penalty is wrong, and if I've learned anything from the moral position staked out therein, it is that the state shouldn't play arbiter in life or death decisions because it doesn't always have the best interests of its constituents at heart, and instead should focus on providing the best possible social welfare to all. That applies universally to the health care of women and the way we care for our young. Too often as people here note anti-abortion voters also want to restrict access to care for women's health and limit services for vulnerable newborn children, relying too heavily on the individual's capability to care for a child.
I am sympathetic to the position that abortion is no different from murder because I haven't found a good and complete argument, scientific or otherwise, that rebuts it. I think the state should work to reduce the number of abortions, but keep the procedure safe and access to it legal. It's a complex and frustrating position to support given the moral implications, and much smarter people than me do a better job grappling with it.