Scientists discovered that milk that had been pumped contained higher levels of potentially harmful bugs compared to milk received directly from the breast.
The study also revealed that the proportion of “helpful” bacteria transferred from the mother via the baby’s mouth during natural breastfeeding, was lowered.
Increasing evidence suggests this oral bacteria contributes to a healthy gut “microbiome”, or microbial community, in babies.
Breast milk has been found to contain a complex cocktail of bacteria that may be important in establishing “friendly” bugs in the infant gastrointestinal tract.
Experts believe disruption to the infant microbiome could leave children vulnerable to allergies, asthma or obesity.
“Although previously considered sterile, breast milk is now known to contain a complex community of bacteria that helps establish the infant gut microbiota,” study authors write.
“If this process is disrupted, the infant may develop a dysbiotic microbiota, causing predisposition to chronic diseases such as allergy, asthma and obesity.”
It’s not fully clear how bacteria entered the gut and scientists wanted to study whether breast pumps could be a source of new, and potentially harmful, bugs.
For the study, published in the journal Cell Host & Microbe, scientists looked for bacteria in breast milk samples from 393 healthy mothers three to four months after giving birth.
The team found the bacteria levels of milk being fed to the babies differed greatly.
Milk fed to babies from breast pumps contained higher levels of potentially harmful “opportunistic pathogens” such as Stenotrophomonas and Pseudomonadaceae.
On the other hand, direct breastfeeding without a pump was associated with microbes typically found in the mouth, as well as greater bacterial richness and diversity.
“To our knowledge, this is among the largest studies of human milk microbiota performed to date,” says senior study author Meghan Azad, from the Children’s Hospital Research Institute of Manitoba.
“This study considerably expands our understanding of the human milk microbiota and the factors that might influence it. The results will inspire new research about breastfeeding and human milk, especially related to pumping.”
Further research needed
The study authors admitted some limitations to the study but concluded that further research was needed to explore the implications on the results for infant health and development.
Mums who do express milk to feed their babies’ certainly shouldn’t panic following the study results.
“We know that there is a great deal we are only just beginning to understand about the human microbiome and the function of vaginal birth, breastfeeding, skin to skin contact with newborns and more, in the development of a baby’s personal colony of bacteria,” Milli Hill, birth expert at The Baby Show and author of ‘The Positive Birth Book’, tells Yahoo UK.
“We already know that breastmilk contains a far richer and diverse set of helpful bacteria than formula milk, so to anyone who has no choice but to express, I would say, keep going,” she continues.
“The bacterial diversity and content of the pumped milk may not be as good quality as milk direct from the breast, but it will almost certainly be of much better quality than formula.”
Milli is keen that the results shouldn’t cause new mums who do choose to express milk to panic.
“However women feed their babies they are all working extremely hard to do the right thing for their personal circumstance and I don’t think this research should make them unduly anxious,” she says.
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