Breastfeeding could protect babies from respiratory illness, says a study adding to mounting evidence that the longer a mother breastfeeds her infant the greater the health benefits.

Researchers identified five groups — formula-fed only, full breastfeeding for less than one month, full breastfeeding from one to four months, full breastfeeding from four to less than six months and full breastfeeding for six months or more. Full breastfeeding allows for the use of formula on less than a daily basis. They then looked at the percentage of children in each group who experienced pneumonia, wheezing and recurrent (three or more) colds or ear infections. The results showed the protective effects of breastfeeding. They found that the health benefits of the additional two months of full breastfeeding continued to protect babies from respiratory illnesses through their second birthdays.