Last Updated: 2002-11-12 11:47:50 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Breast-feeding does not prevent infants from developing colic, the discomfort leading to incessant and inconsolable crying that some infants suffer from during the first weeks of life, researchers report.

Infant colic tends to peak during the first 6 weeks of life and taper off by the end of the second month. There is no known cause, and studies have yielded conflicting results on whether factors such as parental smoking and breast-feeding might increase the risk. Breast-feeding is thought to boost immunity and enhance the bond between the mother and infant.

But according to the current report, there was no association between the source of infant nutrition at 1 week of age and the development of colic at 6 weeks. Twenty-three percent of breast-fed babies were described as having colic, compared with 21% of infants who received only formula and 29% of infants who received a combination of breast milk and formula.

The results contradict the notion that an intolerance to a protein in formula or breast milk is the source of infant colic and argue against changing an infant's diet, according to Dr. Tammy J. Clifford from the University of Western Ontario in Canada and colleagues.

And while the cause of colic remains unclear, the findings might ease the fears of some parents that they are somehow to blame.

"We provide further evidence that parents are not responsible for their infants' colic," the researchers write in the November issue of the Archives of Pediatrics and Adolescent Medicine.

The findings were based on interviews with 856 mothers who had given birth to full-term infants. The mothers filled out questionnaires at 1 week and again at 6 weeks postpartum. At 6 weeks, nearly one fourth of mothers reported that their infants were colicky, or cried at least 3 hours a day for 3 days a week.

Colic was more prevalent among babies born to mothers who reported feeling anxious, drinking alcohol 6 weeks after giving birth or doing shift work during pregnancy. Married women and those with a common-law partner were 70% less likely to have a colicky baby, the investigators found.

Still, "much work remains to be done to improve our understanding of the underlying processes responsible for colic and to minimize their potential effects on families, particularly those who are already at elevated risk of distress from less-than-ideal financial, social, and/or medical circumstances," the researchers conclude.

SOURCE: Archives of Pediatrics and Adolescent Medicine 2002;156:1123-1128.

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