The study also found that moms who use expressed breast milk - either pumped or expressed by hand - typically transition their babies to infant formula feeding sooner than their breastfeeding peers.
"Breast feeding is the unequalled method for feeding infants," said Marie Tarrant, director of nursing at University of British Columbia in Canada.
"It has been previously determined that breastfeeding is important for the nutrition, immunology, growth and development of infants and toddlers," Tarrant said.
Researchers, including Dorothy Bai of the University of Hong Kong, studied the infant feeding practices of more than 2,000 mothers living in Hong Kong.
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They found that during a five-year stretch, mothers moved away from directly breastfeeding their infants to using expressed breast milk, which is usually delivered via a bottle.
"New mothers may believe there is no difference between expressed breast-milk feeding and direct feeding at the breast," said Tarrant.
"Although expressed breast-milk feeding provides greater benefits than infant formula, bottle-feeding may increase the risk of respiratory issues, asthma, rapid weight gain and oral diseases," she said.