An example of how an attempt to abort (/kill) could have taken a human life.
See: Baby Miraculously Survives Abortion, Expected to Live a 'Normal' Life
WCF Q. 68 What is required in the sixth commandment?
Ans: The sixth commandment requireth all lawful endeavors to preserve our own life, and the life of others.
WCF Q. 69 What is forbidden in the sixth commandment?
Ans: The sixth commandment forbiddeth the taking awaay of our own life, or the life of our neighbor, unjustly, or whatsoever tendeth thereunto.