Infant colic is characterized by excessive and inconsolable crying, hypertonicity, and wakefulness, mainly in the evening. An estimated 5 to 28 percent of infants have colic during the first few months of life. The widely cited “rule of threes” defines a colicky infant as one who is healthy and well-fed but cries for a total of at least three hours per day, more than three days in any one week. Onset is usually between the second and sixth weeks of life, and remission of symptoms generally occurs by three months of age. Although colic is thought to be a self-limited condition, it can be overwhelming to parents over a substantial number of weeks. One concern, moreover, is the potential lasting impact of colic on maternal mental health. Clifford and colleagues studied the prevalence of colic in infants three months of age and the proportion of infants identified with colic at six weeks of age who had symptom resolution by three months of age. They also studied factors that predicted which infants would have resolution of colic by the age of three months and observed the impact of colic on maternal mental health.

The investigation was a prospective cohort study of mother-infant dyads. A questionnaire was mailed to mothers approximately one week after they were discharged from the postpartum ward of a London hospital. The questionnaire requested information about the source of infant nutrition, prenatal and postnatal health behaviors, demographics, and biologic factors. It also included standardized instruments to assess maternal anxiety, postnatal depression, and social support. Another questionnaire, which did not include the anxiety, depression, and social support assessments, was mailed to the mothers at six weeks and three months after delivery.At these times, the mothers also were asked to complete the Barr Baby's Day Diary or the Ames Cry Score. A follow-up questionnaire that included standardized measures of anxiety and depression was sent to the mothers at six months postpartum.

In the 547 mother-infant dyads participating in the study at three months, 35 infants (6.4 percent) had colic at three months of age, compared with 131 infants (23.9 percent) who had colic at six weeks of age. The distribution of crying or fussing (see accompanying figure) was determined on the basis of information from 320 diaries that were returned after the infants were three months old. Girls were more likely to have colic that resolved by three months, and the mothers of infants with colic that remitted by three months of age were more likely to have been employed outside the home during pregnancy, to have received pain medication during labor or delivery, and to have consumed caffeine or alcohol during the postpartum period. The mothers of infants who had colic at six weeks of age did not have significant differences in rates of anxiety and depression, compared with the mothers of infants who did not have colic.

The authors conclude that colic usually is a self-limited condition that does not result in long-lasting negative effects on maternal mental health. They add that physicians should educate parents about colic and offer support during what can be a difficult period. Continued research is needed to determine the cause of colic.