Newborn babies are admitted to Neonatal Intensive Care Units (NICU) in many hospitals in the United States, according to a new report.
NICU's are for babies who are born prematurely before 37 weeks or those with low birth weights, who are considered high-risk.
Dartmouth researchers analyzed nearly 18 million births from 2007-2012, and found that the number of babies who were treated in NICU's grew from 6.4 percent to 7.8 percent.
The researchers said that many newborns admitted to NICU's do not fit the high-risk criteria. It is a potential sign that these expensive NICU's are being overused.
"An increase of this level over six years raises questions. Infants admitted to the units are increasingly likely to be of normal birth weight. More than half of all admissions are for normal or high-birth weight newborns. This suggests the need for further study since the units were initially developed to care for the most premature infants," said study author Wade Harrison, an urban health scholar at Geisel School of Medicine at Dartmouth, in New Hampshire.
The researchers also found that in 2012, half of NICU admissions were for normal birth weight babies or those born at 37 weeks or more.
Experts said that more research is need to determine why babies were admitted to NICU's.