From start to finish. There is nothing in the Bible about abortion. Not one word. The religious right hangs their hat on God's professional of love for John the Baptist when he was in the womb. That's pretty thin.
I hang my hat on the idea that women were created not to carry every fetus to term. Approximately 1/3 of all pregnancies end in a miscarriage. If every life is sacred, why does that happen? In reality, there are many times in early civilization when it would be unwise to become pregnant - during famines, wars, or on long dangerous journeys. Women have always needed to pick and chose the right time to have a baby so as not to put their own lives and that of others at risk.
The lack of labour law protections for working women who become pregnant in the US, results in many women having to use the option of abortion. Women in more enlightened countries have better options and hence fewer abortions.