Colic in infants

Colic in infants: In‑depth analysis of causes and mechanisms

Colic is one of the most puzzling and exhausting conditions that parents face in the first months of a child's life. It is not a disease nor a diagnosis in the classical sense, but rather a behavioral syndrome characterized by episodes of prolonged, intense, and inconsolable crying in an otherwise healthy infant. Understanding that this is not a sign of illness or parental error is the first step toward getting through this difficult period. This condition is a diagnosis of exclusion, meaning that before assigning it, the physician must rule out other problems such as reflux or allergy.

What is colic? "The rule of three"

The classic definition of colic still used by pediatricians was proposed by Dr. Morris Wessel in 1954. It is known as "the rule of three":

• Crying lasts more than 3 hours a day.
• It occurs more than 3 days a week.
• And it persists more than 3 consecutive weeks.

Episodes usually start suddenly, often at the same time of day (classically in the evening, from 18:00 to 22:00). During an episode the baby appears to be in severe pain: it cries piercingly, its face reddens, the abdomen becomes tense, and the legs are drawn up against the belly. Comforting the infant at this moment is extremely difficult. Colic typically begins at 2–3 weeks of age, peaks at 6–8 weeks, and, much to parents’ relief, resolves spontaneously and without trace by 3–4 months.

Why does it occur? Modern theories

Despite decades of research, a single definitive cause of colic has not been identified. Modern science leans toward a multifactorial condition rooted in the immaturity of several bodily systems simultaneously.

• Immaturity of the nervous system: This is one of the leading theories. The infant’s nervous system is not yet able to adequately process and filter the flow of stimuli received throughout the day (light, sounds, touches). By evening overload occurs, and crying becomes a "release" mechanism to discharge accumulated tension.
• Immaturity of the digestive system: It was previously thought that gas pain caused colic, but the view has changed. Gases are more likely a consequence rather than a cause. During prolonged crying the baby swallows a lot of air, leading to bloating.
• Microbiome development: The colonisation of the gut with bacteria is very active in the first months. An imbalance of the microflora and fermentation processes may cause discomfort that contributes to colic.
• Hormonal factor: There is a theory linking colic to fluctuations in certain hormones, such as serotonin, which affect intestinal motility and pain perception.

Evidence‑based methods of helping with colic focus not on "treatment" but on soothing the baby and creating conditions that resemble the womb environment. This is described in detail in the article about the "fourth trimester".