Helping these fragile infants survive and thrive costs the nation at least $26 billion a year, and there's little likelihood of improvement soon, says a sobering report from the Institute of Medicine.
That's because doctors don't know the cause of most preterm births or how to prevent them, and have few good ways even to predict which women will go into preterm labor, concludes the report, which calls for urgent research to try to turn the tide.
That is likely to come as a surprise to many pregnant women. Happy stories of the tiniest preemies who survive are common enough that there's a widespread false sense that modern medicine is conquering prematurity, Iams lamented.
Scientifically, too, "there's just enormous ignorance" about even the basics of prematurity's causes, added Dr. Richard Behrman, a Menlo Park, Calif., pediatric specialist who chaired the institute's probe, the AP reports.
A full-term pregnancy lasts from 38 to 42 weeks. Babies born before completion of week 37 are premature. Those born before 32 weeks face the greatest risks of death - about one-fifth don't survive a year - and devastating disabilities such as cerebral palsy and retardation. But even babies born just a few weeks early can face developmental delays and other problems.