New parents are sometimes blindsided by how much newborns cry. Antenatal classes spend more time on labour than on the weeks afterwards, when the reality of living with a baby who cries for an average of two to three hours a day — and sometimes considerably more — can be both exhausting and frightening. When a baby cries inconsolably and nothing helps, the failure to soothe feels personal, and the fear that something is terribly wrong is hard to suppress.
Understanding the normal range of newborn crying changes this experience significantly. Not because it stops the crying, but because contextualising it — knowing that the peak at six to eight weeks is expected, that it will reduce, that this is what babies do across all cultures and parenting styles — reduces the sense of desperate personal failure and allows parents to cope better.
Healthbooq (healthbooq.com) covers newborn behaviour and parenting in the first months.
The Normal Crying Curve
Researchers including Wessel (1954) and, more systematically, Ian St. James-Roberts and others have documented the developmental trajectory of infant crying. From birth, crying time increases through the first four to eight weeks and then decreases through the rest of the first year. The increase is not caused by any specific problem — it is a feature of normal newborn neurodevelopmental maturation.
At the peak (typically around six to eight weeks), the average infant in multiple cross-cultural studies cries for approximately two to three hours per day. Around 20 per cent of infants cry for three or more hours per day (the traditional "colic" threshold), and a smaller proportion cry for even longer. After two months, daily crying time in most infants reduces measurably over each subsequent month.
This pattern is remarkably consistent across different cultures, feeding methods, and caregiving styles. Extended carrying cultures (where infants are held continuously) have somewhat lower crying rates, but the developmental curve — low at birth, peak around six to eight weeks, gradual decline — is present across all populations studied.
The PURPLE Crying Concept
Ronald Barr, a neonatologist and researcher at the University of British Columbia, developed the PURPLE crying programme as a public health education intervention. PURPLE is an acronym describing the features of this peak crying period:
P — Peak of crying: it peaks and then reduces
U — Unexpected: comes on and stops without explanation
R — Resists soothing: doesn't always respond to caregiving attempts
P — Pain-like face: may look like pain even without pain
L — Long-lasting: can go on for hours
E — Evening clustering: often worse in the late afternoon and evening
The educational purpose of this framing is partly to normalise the experience and partly to address the context in which non-accidental head injury (abusive head trauma) most commonly occurs: a caregiver pushed beyond their limit by a crying infant they cannot console. The intervention includes the explicit message: "It is never okay to shake a baby." Multiple trials have shown that PURPLE crying education reduces both parental distress and rates of abusive head injury.
Colic and Its Meaning
"Colic" (traditionally defined as crying for more than three hours per day, more than three days per week, for more than three weeks, in a baby who is otherwise healthy and well-fed — Wessel's criteria, 1954) is a description of the upper end of the normal crying distribution, not a diagnosis of a specific cause. The name is misleading: it implies gut-related pain as the cause, but the evidence for gut problems as the primary driver of peak-period crying is weak.
Most infants diagnosed with colic have no identifiable organic cause. The crying resolves around the same time as non-colic crying reduces — at around three to four months. This timing is consistent with a maturational neurological process rather than a specific pathological cause.
Cow's milk protein allergy (CMPA) can cause significant crying in formula-fed infants and, via breast milk, in breastfed infants. A brief trial of hypoallergenic formula or maternal dairy exclusion is reasonable in infants with very prolonged or unusually intense crying, particularly if there are other allergy features (blood in stool, eczema, poor weight gain).
Gastro-oesophageal reflux is sometimes treated as a cause of colic, but systematic evidence reviews have not consistently supported acid suppression treatment as beneficial for crying in otherwise-healthy infants.
Soothing Strategies
Evidence-supported soothing approaches for peak-period crying include: holding and carrying, rhythmic movement (rocking, swinging, car journeys), white noise at moderate volume (matching womb-like constant background sound), sucking (dummy or breastfeeding), warmth, and swaddling in young infants. None of these work every time, and many work only intermittently. The most important message is that the failure to soothe is not the parent's fault.
When to seek medical assessment: crying that is truly continuous without any settling periods, high-pitched screaming inconsistent with the usual crying character, crying associated with other symptoms (fever, vomiting, rash, change in behaviour), or a sudden change in an established crying pattern all warrant same-day GP assessment.
Key Takeaways
Newborn crying follows a predictable developmental curve: it increases from birth, peaks at around two months (averaging two to three hours per day in many studies), and then gradually decreases. This pattern is cross-cultural and occurs regardless of parenting style, feeding method, or parental responsiveness. The PURPLE crying concept (developed by Ronald Barr at the University of British Columbia) describes this peak period and is used in public health education to normalise the experience and reduce stress-related abuse. Persistent crying that deviates from this pattern or is accompanied by other symptoms warrants medical assessment to exclude pathological causes.
