Caesarean sections could pose a risk for some babies born premature.
Researchers found Caesarean sections didn't reduce the odds of complications for preterm babies who are small for their age.
In fact, premature babies born via Caesarean section had a higher rate of breathing problems.
The March of Dimes has been working to educate people about what it believes are medically unnecessary Caesarean sections, especially before 39 weeks.
Researchers at Johns Hopkins and Yale Universities conducted the study.
Copyright 2012 KPHO. All rights reserved. CNN contributed to this report.