Supplementing breast-feeding with formula may be good for some babies in the early days of life.

Exclusive breast-feeding is widely recommended by experts, and rates of breast-feeding have risen. But so have rates of readmission for dehydration and jaundice attributable to inadequate nutrition.

Researchers studied 164 infants who exclusively breast-fed one to three days after birth but whose weight loss was greater than the 75th percentile for their age. Their mothers had not yet begun mature milk production.

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Half were randomly assigned to exclusive breast-feeding. The other half got 10 milliliters of formula at the end of each breast-feeding session, which was discontinued when the mothers’ milk came in two to seven days later.