New mothers who can't nurse their babies are turning to online sources, typically strangers with ample supplies, for breast milk.
But a new study found high levels of harmful bacteria and contamination in breast milk purchased online.
According to NBC News, researchers tested 101 milk samples bought on varies milk-sharing websites and found that almost three quarters were not safe for babies, especially preemies. The milk typically sells for $1 or $2 per ounce from sites.
"If you buy milk on the Internet, you have no idea what you're getting," said Sarah Keim, who led the study at The Research Institute at Nationwide Children's Hospital in Columbus, Ohio. "A buyer would just have no way of being able to know with the information they have whether that milk is safe."
The findings were likely the result of poor hygiene during milk collection, the use of either unclean containers or unsanitary breast milk pump parts, or compromised shipping practices, Keim said.
"I can't think of something you can buy online where you have less ability to validate the quality," Keim told NBC News. "Even frozen milk was just as contaminated as thawed milk. There wasn't a whole lot recipients can rely on to know that it's OK."
According to Keim, it is "totally normal" for there to be certain bacteria in human breast milk.
"[Some are] very important and healthy for babies and the development of their immune system and digestive system," she said. "But we're a little suspicious of some of the milk."
None of the shipped breast milk tested positive for HIV, the virus that causes AIDS. But one in five samples, 20 percent, had traces of cytomegalovirus, which can lead to disease in babies with weak immune systems.
Other bacteria found included coliform, staphylococcus and streptococcus bacteria in the milk purchased online. The contamination was associated with poor milk collection, storage or shipping practices, the analysis showed. Nineteen percent of sellers did not include dry ice or another cooling method when shipping, the study found.
"We were very surprised by our findings," Keim said. "Besides bacterial contamination and viruses that could be in the milk, you could be exposing your infant to chemical contaminants, pharmaceuticals or drugs as well."
Nearly 75 percent of breast milk bought through the site OnlyTheBreast.com was tainted with high levels of disease-causing bacteria, including germs found in human waste, according to NBC News.
"We have made the decision to transition away from offering breast milk classified ads and in the near future completely remove them," site founder Glenn Snow said in a statement.
The U.S. Food and Drug Administration recommends against feeding babies milk bought over the Internet, but doesn't regulate its sale. Instead, officials said they're working to form a new milk bank program, Milk for Babies, that would partner with a laboratory to offer screened milk while still permitting donors to be reimbursed.
"We are convinced that a more safety-centered approach must be taken to secure milk sharing," officials said.
Health officials routinely urge women to nurse their babies exclusively for the first six months and along with other foods for the first year. About 77 percent of U.S. babies are fed their mother's milk at least once, according to the Centers for Disease Control and Prevention.
Founders of a few sites included in the study have responded to researchers' results.
"A blatant attack on women attempting to feed their babies is cruel and you should feel ashamed of yourself for spreading misinformation," Khadijah Cisse, a midwife who founded MilkShare, a portal for connecting women cited in the new research, said in an email to NBC News. "Anyone can type up any bit of lies they want and make claims. Breast milk is supposed to contain bacteria."
Any feeding system except a mother breast-feeding her own child carries some risk, said Shell Walker, founder of Eats on Feets, a milk-sharing portal.
"There's not a single feeding method outside of that closed biological system that doesn't warrant close monitoring," she said.
