Why do you keep saying "preterm" instead of "premature"?

Because that's what the people at CPMC say, and what, all of a sudden you know better than them?  Actually, it makes sense when you think about it.  Even a term baby is hardly "mature," and it's all a matter of whether the child has reached an ordinary gestational term, not whether it is "mature" or "premature."  "Preterm" has the benefit of being more accurate, and perhaps sounding slightly less judgmental of the baby.