There are many things not mentioned in the Scripture...they could not comprehend the idea of purposely wrenching a child from a mother's womb. Why would God have spoken of it? He told them to multiply, killing the children would have been contradictory to HIi own command. Actually, child sacrifce was condemned. Don't see much difference between that & abortion.
The same holds true for many "unmentioned" evils. Counterfeiting fits the "do not covet" directive as well.
I think that the fact that God said to Jeremiah: "I knew you in the womb" puts abortion in proper context for both Christian and Jew.