Crying, fussing and colic behaviour in breast- and bottle-fed infants

Persistent infant crying and "colic" have been linked in some studies to fe eding, but this association has not been tested in a planned longitudinal s tudy comparing breast- with formula fed babies. We used validated maternal diaries of infant behaviours, kept for three days at both two and six weeks of infant age, in a comparative study of 97 breast- or formula fed babies. The total duration of overall crying rose significantly between 2 and 6 we eks in breast-fed infants and fell in those fed formula. At 6 weeks, breast -fed infants cried an average of almost 40 minutes more per day than formul a fed infants; and 31% cried for more than three hours per day, compared wi th only 12% of the formula fed group. At six weeks, breast-fed infants also slept almost 80 minutes less per day than the formula fed babies. While si x weeks is the established peak age for infant crying, those fed formula pe aked much earlier and at 2 weeks intense crying/colic behaviour occurred in 43% of formula fed babies and just 16% of those fed by breast. These findi ngs link the timing of the infant crying peak to the mode of feeding. Our d ata indicate that any regimen designed to reduce crying should commence in the neonatal period in formula fed infants. (C) 1998 Elsevier Science Irela nd Ltd. All rights reserved.