Even extremely low birth weight premature babies should be given breast milk while they are in a hospital's intensive care unit because it appears to boost their mental development, concludes a study in the journal Pediatrics.
The study found that preemies fed breast milk had greater mental development scores at 30 months of age than infants who were not fed breast milk.
Moreover, infants fed breast milk were less likely to have been re-hospitalized after their initial discharge than were the infants not fed breast milk.
The study involved 773 U.S. babies born extremely underweight -- less than 2.2 pounds (1 kg) -- between 1999 and 2002. The children were divided into five groups by the quantity of breast milk they ingested while in the NICU.
The majority of the infants had been given at least some breast milk while in the NICU administered by a feeding tube that dripped the breast milk into their stomachs; 593 ingested some breast milk, while 180 ingested none.
Both groups experience the same amount of physical growth. But the babies given breast milk got higher scores on a test measuring their overall intelligence at 30 months of age, with the highest scores showing up among the children who had received the most breast milk as infants.
As well, for every 10 mL/kg per day increase in breast milk, the risk of rehospitalization between discharge and 30 months decreased by five per cent.
Mothers who provided breast milk for their infants tended to have more education than those who did not. However, in their analysis of the data, the researchers mathematically compensated for the mothers' educational levels.
With this adjustment, the researchers concluded that consumption of breast milk had a positive effect on infants' mental development scales, independent of mothers' educational levels.
"These findings strongly suggest that, whenever possible, preterm infants should routinely be given breast milk during their stay in the intensive care unit," said Dr. Duane Alexander, director of the National Institute of Child Health and Human Development, which backed the study.
Previous studies have found that infants who ingest breast milk are able to leave the neonatal intensive care unit sooner than infants receiving formula.
The Canadian Paediatric Society recommends that children be breastfed exclusively for at least six months.
