MONDAY, Feb. 22, 2016 (HealthDay News) -- More hospitals give tiny preemies donated breast milk instead of formula, and the babies appear to benefit from it, a new study suggests.
Researchers found the number of California hospitals offering donor breast milk rose substantially between 2007 and 2013 -- from about 21 percent of all newborn intensive care units (NICUs) to 41 percent.
Over those same years, NICUs that made the change showed an increase in moms who'd begun breast-feeding by the time their babies were discharged.
Infants also were less likely to develop a potentially dangerous gut infection called necrotizing enterocolitis, according to findings published online Feb. 22 in the journal Pediatrics.
It's not clear that donor breast milk itself drove those changes, said senior researcher Dr. Henry Lee, of Stanford University's division of neonatal and developmental medicine, in California.
"This doesn't prove cause-and-effect," he said, "but it's good to see correlations going in this direction."
There had been some concern that donor milk could actually get in the way of moms' success with breast-feeding, Lee noted. "So, it's encouraging to see this was not the case," he said.
When women give birth very preterm, breast-feeding can be a challenge. Ideally, Lee said, mothers are able to use a breast pump so their tiny newborns can be fed via bottle. But often, women can't express enough milk.
In those cases, donor breast milk is considered the next-best option. Hospitals get that milk from nonprofit milk "banks." Currently, about two dozen milk banks serve most U.S. states and parts of Canada, according to the Human Milk Banking Association of North America.
Mothers who have "extra" breast milk can donate it to the banks, after undergoing a screening process that includes blood tests for diseases like HIV and hepatitis. The milk is pasteurized, Lee said, and tested for bacteria.
Lee said that at his hospital, when preemies' moms cannot express enough breast milk, they're offered the option of supplementing with donor milk. It's no extra cost to families, he said.
But while experts consider breast milk the best nutrition for infants -- including very preterm babies -- it hasn't been clear whether using donor milk in the NICU benefits preemies.
Lee's team found that positive changes occurred at the same time that more NICUs started using donor milk.
In 2007, only 27 of 126 California NICUs were using donor milk. By 2013, that had risen to 55 of 133 NICUs. Across all hospitals, more moms started breast-feeding over the study period and the rate of necrotizing enterocolitis dropped by about half, the study found.
But the odds of improvement were greater at hospitals that started using donor milk, the study found. At those hospitals, about 53 percent of mothers had started breast-feeding by the time their babies were discharged in 2007; in 2013, that figure was almost 62 percent.
Over those same years, preemies' rates of necrotizing enterocolitis fell from 6.6 percent, to just more than 4 percent.
There is "very strong" evidence that breast milk helps ward off enterocolitis, said Dr. Lydia Furman, a pediatrician at Rainbow Babies and Children's Hospital, in Cleveland.
So, she said, it makes sense that donor milk -- which retains the substances thought to protect against enterocolitis -- could benefit preemies. But she also stressed that donor breast milk is no magic bullet.
Furman, who wrote an editorial published with the study, said that hospitals' use of donor milk is a "marker" of broader progress.
"It takes a coordinated program to make donor milk available," Furman said. "And that kind of coordination probably happens in NICUs where the value of mothers' milk is greatly appreciated."
So, she said, donor milk is one way that hospitals can encourage moms of preemies to breast-feed, and reduce enterocolitis infections. "But," she added, "we need a range of strategies to help all women breast-feed, whether their baby is preterm or full-term."
That, said Furman, can include educating families on the value of breast milk, allowing moms and newborns to have lots of skin-to-skin contact starting right after birth, and helping women learn how to use a breast pump.
Furman pointed to another issue that came up in this study: Black and Hispanic women had lower rates of breast-feeding than white women, and their babies had higher rates of enterocolitis.
Those disparities, Furman noted, have a host of factors behind them that no single measure -- donor breast milk, or otherwise -- can tackle. For one, low-income women are less likely to have the types of jobs that offer paid maternity leave, or time during the day to pump their breast milk.
"Until the U.S. joins the rest of the world in giving women paid maternity leave, we won't be able to fully address disparities in breast-feeding," Furman said.
The Human Milk Banking Association of North America has more on donor breast milk.