Yes, we certainly need to begin with nuance such as this. And that should include calling into question the church's teachings, which seems to lack such nuance.

You might be interested in a recent book by husband-and-wife law professors Sherry F. Colb and Michael C. Dorf, "Beating Hearts: Abortion and Animal Rights." Their analysis of the morality of these issues, legal approaches to them, and the movements associated with them, arranged more or less in a compare-and-contrast discussion, is well done. Their own attitude on abortion, which they explain well, is that it should be legal, out of regard for the interests of the pregnant woman, but that once the fetus becomes sentient (NOT viable; prior to that, the fetus is not a being holding a stake), the woman is faced with a serious moral challenge. My guess is they would approve the provision that an ultrasound be offered her.