Many of the pro-life movement view abortion as murder because they believe that "life" begins at conception; when sperm meets egg.
Of course, when life begins is a vital piece of information when it comes to rulings about abortion.
The Islamic perspective is that life begins 120 days after conception. The Prophet (peace be upon him) said:
"Verily the creation of each one of you is brought together in his mother's womb for forty days in the form of a nutfah (a drop), then he becomes an 'alaqah (clot of blood) for a like period [forty days], then a mudghah (morsel of flesh) for a like period [forty days], then there is sent to him the angel who blows his soul into him and who is commanded with four matters: to write down his rizq (sustenance), his life span, his actions, and whether he will be happy or unhappy (i.e. whether or not he will enter Paradise)." Sahih Bukhari and Muslim.
The scholars differ on their views on abortion (since abortion was not around at the time of the Prophet, peace be upon him, and so he did not address it).
Some scholars still view that abortion is wrong, regardless of when it is done.
The majority of scholars, however, view that abortion is acceptable, if it is done during the first 120 days. The majority of the scholars also agree that the woman should first try taking the morning after pill, or the Plan B contraceptive.
Of those scholars, some say it is okay if the woman is experiencing health issues with the pregnancy, or if she was raped; basically dire circumstances.
Others view that abortion is fine if the pregnancy and raising a child would cause mental anguish to the woman (and her husband) or if she just can't handle a pregnancy at the moment.
A general rule in Islam is to take the opinion of the majority of scholars more seriously, since there is less room for individual error.
In conclusion, the majority of Muslims view that abortion, if done during the first 120 days, is allowed, and for a variety of reasons.
Source: Islam Q&A