@Drmowinckels Not sure, I've never thought about it but I've mostly used 'prenatal/postnatal' to indicate a stage or phenomenon and 'fetal' to indicate the something pertaining to the actual fetus.
I don't think I have a linguistic basis for this though, just an intuitive sense of which goes where, and that could be entirely wrong.
@aazad Cool, thank you! This is what others have replied too, so that aligns well.