Preventing pre-term labor

It was announced last week that researchers believe they have come up with a profile of the metabolic by-products in amniotic fluid that can flag women who will go into preterm labor. This means there could be a test to predict who's at risk for it. Though I wonder whether, if it's an amniotic fluid test, there isn't a risk of starting preterm labor through whatever process is used to collect the fluid. I'm guessing that it would not be a routine test, but rather one that is used selectively on women who have had preterm labor before.

Preterm birth (meaning before the 37th week gestation) occurs in about 12% of U.S. births.