Crying in infants is considered a normal developmental behavior with great variability between individuals in the amount of crying. There has been no clear singular definition of what constitutes normal versus excessive crying, known as colic. Observational studies in various settings have shown certain patterns that could constitute normal crying patterns in infants:
Crying increases progressively from birth and peaks at about 6 weeks of life and subsequently decreases. One meta-analysis showed an average duration of crying to be 110 to 118 min per day in the first 6 weeks and then decreasing to 70 minutes per day by week 12.
There appears to be a diurnal rhythm, with peak crying clustering during the evening hours, and this is most apparent during the peak crying time at 2 months.
Considerable variability exists in the amount of crying not only between different individuals but also day-to-day differences in the same infant.
Colic is a descriptive term for the amount and quality of crying that appears to be outside the expected or “normal” crying behavior observed in otherwise well infants. As a descriptive term, it does not imply any pathology and is generally believed to be a benign process that self-resolves with time.
The pattern of crying observed in infants with colic is the same as that observed in normal infants in terms of peak at 6 weeks and then a steady decline in frequency, and duration of crying, but the episodes of crying are longer and more high-pitched and fail to improve with the normal soothing behaviors such as carrying or rocking. Additionally, family dynamics, psychosocial factors, and expectations affect the parent perception of what constitutes excessive crying. Infants perceived to be crying excessively by their parents cause a considerable amount of distress in the caretakers and are at higher risk for harm such as shaken baby syndrome. One study found that 5.6% of parents had admitted to having shaken, slapped, or smothered the baby to stop the crying.
There are several clinical definitions for qualifying what constitutes excessive crying for diagnostic purposes:
The most recognized in clinical practice and research is Wessel’s “rule of threes.” It requires that in an otherwise well and fed infant the crying episodes last 3 or more hours per day, occur on 3 or more days per week, and persist for at least 3 weeks.
The Rome IV criteria is another classification system that requires confirmation of total crying time by a parental diary to be 3 or more hours per day, in addition to lack of failure to thrive or evidence of other systemic illness. The episodes of crying have to start and stop without obvious precipitating factors.
Another term used to describe colic is a period of PURPLE crying. This acronym describes the timing as well as the morphology of crying, taking into account the ...