Twenty-two trials with a total of 1,217 participants were included in the review. Of these, 9 (n=593) used the Weasel case definition. The authors considered that all included trials had used adequate randomisation, and that 12 of the trials (n=638) had adequate double-blinding. Five trials (n=364) were considered adequate in all three categories.
Pharmaceutical interventions.
Of the 3 trials of simethicone, 1 reported significantly fewer episodes of crying, and the remaining 2 found no significant benefit.
All 3 trials of dicyclomine reported positive results. Two of the trials reported a higher (8%) incidence of adverse events in the treatment group than in the placebo group.
The single trial of methylscopolamine found that it had no significant impact on the symptoms of infant colic, but that adverse effects were more common in participants receiving the active treatment.
Dietary interventions.
A hypoallergenic diet was adopted by breast-feeding mothers in 2 studies. One found significantly positive results in terms of mean daily duration of symptoms, while the other found no statistically- significant effect on symptoms when eliminating cow's milk from the maternal diet. Further analysis produced results in favour of a controlled diet.
There were 2 trials investigating the use of hypoallergenic formulas in bottle-fed infants. Both reported significantly positive results, although the data from one of these were not presented in a manner that allowed for comparable interpretation.
Of the 2 trials on the use of soy-based formulas in bottle-fed infants, one reported a significant reduction in mean weekly duration of symptoms, while the other did not report the data in a manner that allowed for analysis of the treatment effect.
Neither of the 2 trials of lactase found any significant differences between treatment and placebo groups.
One trial on the use of fibre-enriched formula in bottle-fed infants found no significant differences between the treatment and placebo groups.
Behavioural interventions.
Neither of the 2 trials of infant carrying showed any reduction of symptoms.
One trial investigating car ride simulators showed no significant differences between the treatment and control groups in either duration of crying or measures of maternal anxiety.
One trial found that parents who received intensive training in parent-infant communication skills and daily counselling reported a significant decrease in mean daily crying. However, this study had several major methodological flaws.
One trial showed a significant improvement in infants whose parents were advised to reduce stimulation, compared with the control group. However, this study also had methodological weaknesses.
Naturopathic interventions.
One trial of herbal tea found a significantly positive effect in the treatment group, in terms of reduced numbers of infants meeting the Weasel criteria for colic. No significant differences were seen in the average numbers of night awakenings, and no adverse events were reported in either the treatment or placebo groups.
One trial of sucrose found a significantly higher number of parent-reported responses in the treatment group than in the placebo group. However, it appeared that in the majority of cases the response lasted for less than 30 minutes. A second trial, which examined infants both with and without colic, found that whilst both groups responded to sucrose and not to placebo, the response in the colicky infants lasted, on average, for less than 3 minutes.