I understand what you wrote but perhaps you have not considered intent well enough. A mother who makes poor choices has no intent to kill her baby, an IVF couple may have no intent to kill their babies, both are incidental the real intent.
Intent is a hard thing to divine and best left to our Lord. I am not even advocating for IVF and see the problems with it, again I am just saying it is not such a clear issue and maybe best left to the couple and their prayers to decide.
If this is your belief, I can only conclude you have no real understanding of what IVF entails, because as I've already said, the process of IVF assumes from the start that embryos (human beings) will be snuffed out.