SOURCES: Jennifer Wu, M.D., obstetrician/gynecologist, Lenox Hill Hill Hospital, New York City; Sept. 8, 2015, news release, Emory University, Atlanta; Journal of the American Medical Association, news release, Sept. 8, 2015
TUESDAY, Sept. 8, 2015 (HealthDay News) -- Advances in treatment are boosting survival and lowering complication rates for babies born extremely premature in the United States, a new study shows.
"Our analysis shows that survival of extremely premature infants and survival without major health problems have improved over 20 years," study author Dr. Barbara Stoll, of Emory University School of Medicine in Atlanta, said in a university news release.
"One of our most important new findings is a significant increase in survival without major neonatal health problems for infants born at 25-28 weeks," she said. A full-term pregnancy typically lasts 40 weeks.
In the study, Stoll's group looked at data on more than 34,600 extremely preterm births -- delivered at between 22 to 28 weeks of pregnancy occurring nationwide between 1993 and 2012.
From 2009 to 2012, the survival rate rose from 27 percent to 33 percent for infants born at 23 weeks, and increased from 63 percent to 65 percent for infants born at 24 weeks, the study found.
There were smaller increases in survival rates for infants born at 25 and 27 weeks, but no change for infants born at 22, 26 and 28 weeks.
Survival without major complications rose about 2 percent each year for infants born at 25 to 28 weeks, but there was no change for those born at 22 to 24 weeks.
Dr. Jennifer Wu is an obstetrician/gynecologist at Lenox Hill Hospital in New York City. She said many factors have combined to help these very tiny newborns survive.
"Several obstetric and pediatric interventions have brought about these improvements," she explained. "A larger percentage of mothers in preterm labor are receiving steroids and this results in accelerated lung maturity [for babies], and respiratory interventions for premature infants have also changed."
However, the study suggests that while improvements have occurred, much more must be done to save babies' lives.
"Although overall survival increased for infants aged 23 and 24 weeks, few infants younger than 25 weeks' gestational age survived without major neonatal [complications], underscoring the continued need for interventions to improve outcomes for the most immature infants," the research team wrote.
Stoll added that, "at the same time, we must focus on reducing the high rates of preterm birth, with approximately 450,000 infants born prematurely in the United States each year."
The study was published in the Sept. 8 issue of the Journal of the American Medical Association.
The March of Dimes has more about preterm labor and birth.