What percentage of infants under 3 months old is affected by colic?

The correct answer is that 10-20% of infants under 3 months old are affected by colic. Colic is commonly characterized by excessive crying and fussiness in otherwise healthy infants. Research findings and clinical observations suggest that this range accurately reflects the prevalence of colic symptoms in this age group. Various studies indicate that the condition is transient and tends to resolve as the infant matures, often by the time they are around 3-4 months old. Understanding that colic affects a significant minority of infants helps caregivers and healthcare providers manage expectations and provide support during this challenging phase for families.

The other options reflect higher prevalence rates which do not align with the established data regarding colic, as studies show that while colic is a common concern, it typically does not impact more than 20% of infants in the specified age range.