There may actually be good biblical support that abortion is wrong, apart from the obvious argument from the sanctity of human life. Really, it should just end there but people always want more proof, and usually for such people there can never be enough proof.
Anyway, according to Alvin J. Schmidt in Under the Influence: How Christianity Transformed Civilization, the Greek word pharmakeia is used in Galatians 5:20 and Revelation 21:8, two lists of sins. The word means "the making and administering of potions" and is usually translated as "sorcery" and "witchcraft", for obvious reasons. However, Greco-Romans commonly used potions to induce abortions, as mentioned by Plutarch, Clement of Alexandria, Minucius Felix, Bishop Ambrose, and several others throughout the centuries (they all used pharmakeia as a method of abortion).
Schmidt points out that Revelation 21:8 is particularly interesting because pharmakeia is condemned immediately after "sexual immorality" - commiting abortion to conceal sin and/or to do away with an unwanted child is probably 99% of the reasons why people continue to have abortions, IMO. It is also worth mentioning that the Didache, an early Christian text, possibly for catechism, dating from the mid first to mid second centuries, condemns abortion - "you shall not kill a child by abortion".
So there you have it. Both pagan and Christian writers showing that pharmakeia, a word used by Paul and John in lists of sins, is used in direct reference to abortions.
BTW, I strongly recommend this book for Christian and non-Christian alike.