Narrator: This is Science Today. Premature babies tend to be anemic -- that is, they don't make enough red blood cells. So they get a lot of transfusions. Pediatrician Dr. Rod Phibbs of the University of California, San Francisco says that in fact, preemies get too many transfusions for their own good.

Phibbs: At least in certain phases of their hospitalization, they get too many transfusions. Nobody argues with transfusing a critically ill baby who's on a ventilator. It's when they are more stable and growing and have very little or no disease that there's been criticism of the practice. And it's not that they never need transfusions, it's that people are too liberal with transfusions.

Narrator: The problem is that as they reach the age at which they would have been born normally, preemies need to be anemic in order to stimulate red blood cell production.

Phibbs: So you see what happens, you keep transfusing them, they never get the signal and you just perpetuate the problem.

Narrator: In the course of a recent study, Phibbs found that preemies did just fine with far fewer transfusions than are normally called for. For Science Today, I'm Steve Tokar.