Seems worth noting that Aquinas also believed all human law should be statutory rather than created by judges, noting that "those who sit in judgment of things present, towards which they are affected by love, hatred, or some kind of cupidity; wherefore their judgment is perverted." So Aquinas, too, fundamentally rejected common law...
Late medieval and early modern law in Europe was informed by Aristotelian and Thomistic understandings of personhood even in places that didn't have a primarily-statutory legal tradition.
But, yes, common law prior to the early nineteenth century or so was that abortion was legal prior to "quickening" and either manslaughter or a serious misdemeanor afterwards.