Researchers tracked around 1,000 extremely low birth weight infants born at 15 hospitals. Three-quarters of the infants -- who weighed less than 2 pounds, 3 ounces -- were fed at least some breast milk while in the hospital, and one-quarter were fed only formula. In tests of mental development administered when the babies were 18 months old, infants who were fed breast milk scored higher than the formula-fed babies.
According to study co-author Dr. Betty Vohr of Brown Medical School, the fatty acids found in breast milk seem to help the infants' brains develop properly. Vohr says that's because the brain development that would usually occur in the womb during the third trimester of pregnancy must instead take place in the neonatal intensive care unit, where the babies don't have ready access to nutrition from mom.
The researchers also took the infants families' income and education into account when scoring mental development, and the breast milk-fed babies still consistently scored higher than the formula-fed babies. Researchers found that the more breast milk the infants consumed, the better they performed on the tests.
This study is the latest in a series of scientific findings that lend increasing credibility to the idea that feeding babies breast milk offers them significant advantages in health, immune function and brain function over babies fed infant formula.