No-one's needed modern science to understand that fetuses grow and eventually become babies when they exit the mother's womb, you know. That's not superstition, that's just readily a observable phenomenon, where science has done little more than increase our understanding of how it happens.
But even the ancients realised that there has to be a transitional point where a fetus becomes more than a vaguely shaped blob of cells and something recognisably human-ish. The principle of "quickening" (and thus when some religions decided to believe a soul had arrived) was based on fetal movement. We can understand this from their primitive if reasonable assumption that movement might be associated with thought. Add a load of science, we now have a very good idea about when certain functions develop in a fetus rather than these sort of crude approximations.
This, then, is the consistency, to which your introduction of mysticism is misleading. The development of a fetus has always, at core, been understood by observation and reason - at least, that available to the knowledge of the time. Religions then imposed their mystical notions on top of it (as they have done for most things).
Your religion's hardline stance isn't even really one of deepest principle. It magicked it up over the last few centuries off the back of wider social movements that turned against abortion, following that trend more than making it.
