Health watchdogs should regulate online sales of breast milk, so prone to contamination that babies may be placed at risk, the BMJ medical journal said in an editorial on Wednesday.
New mums face mounting social pressure to provide breast milk, given its famous nutritional benefits, and more and more are turning to the Internet if they are unable to provide the milk themselves.
Breast milk purchased online is cheaper than that obtained from regulated breast milk banks.
The reason, the editorial said, is that Internet providers cut corners on the cost of checking donors and on storing and shipping the milk in hygienic conditions.
"Unlike donors at licensed milk banks, online sellers are not required to undergo any serological screening, meaning that diseases such as hepatitis B and C, HIV, human T cell lymphotrophic virus and syphilis may not be detected," it said.
The editorial pointed to several published studies highlighting the risks.
One found that 21 percent of tested samples of Internet-bought breast milk were contaminated with a herpes virus called cytomegalovirus, compared to five percent from a regulated bank.
Another found that 92 of 101 online samples tested positive for bacterial growth, likely due to a lack of pasteurisation, and poor shipping and storage conditions.
Another investigation into 102 online samples found that 25 percent arrived with severely damaged packaging and were no longer frozen, leading to more rapid bacterial growth and contamination.
"Other studies identified occasional contamination with bisphenol A and illicit drugs and tampering, including the addition of cow's milk or water to increase volume," the specialists said. "Such contamination cannot easily be detected before infant feeding."
The editorial is lead-authored by Sarah Steele, a lecturer at the Global Health, Policy and Innovation Unit at Queen Mary University London.
Breast milk is not just purchased for babies — gym enthusiasts and cancer patients are also among the buyers, believing it provides a nutritional plus for muscle-building and the immune system.
The editorial called for better regulation of the collection and shipping of breast milk, and improved training for healthcare workers who advise new mothers.
"Milk bought online is far from an ideal alternative, exposing infants and other consumers to microbiological and chemical agents," it said. "Urgent action is required to make this market safer."