Almost every new parent has the same shock around 6 to 8 weeks: the baby cries far more than they were warned about, often inconsolably, often in the evening, often when you've already tried everything. The crying feels like a verdict on your parenting. It isn't.
What helps most is not a new soothing technique. It's knowing the curve — that this peak is coming, that it's normal, that it's measurable, and that it always passes around 3 to 4 months. With that frame, the same hours of crying are still hard, but they stop feeling like personal failure.
Healthbooq tracks crying patterns alongside feeds and sleep, useful when you want to see whether tonight is actually worse or just feels worse.
The Crying Curve, In Numbers
The longest-running observational data on infant crying comes from Brazelton (1962), Wessel (1954), and more recent work by Ian St James-Roberts at the Thomas Coram Research Unit. The curve is consistent across cultures and feeding methods:
- Birth – week 2: about 1 hour of crying a day
- Weeks 3–5: rising — about 2 hours a day
- Weeks 6–8 (the peak): average 2.2 to 2.7 hours a day
- 2–4 months: dropping rapidly
- 4 months onwards: about 1 hour a day, with the day's biggest blocks shifting from "evening" to "tired/hungry/bored"
About 20% of babies cross 3 hours a day at the peak. About 5–10% reach 4 hours or more. The shape of the curve is the same; some babies are simply at the upper end.
The pattern is not caused by anything specific in care. Studies in cultures with continuous baby-wearing (like the !Kung in Botswana) show somewhat shorter total crying times, but the same shape — rising, peak around 6 weeks, fall by 3 months. The curve seems to be tied to nervous system maturation, not feeding, not parental skill, not personality.
The PURPLE Crying Frame
Ronald Barr at the University of British Columbia developed the PURPLE crying education programme to give this curve a name parents could remember and to address one specific thing: shaking. Abusive head trauma — the leading cause of fatal head injury in infants — peaks at the same age the crying does. The triangulation is brutal: the baby is at peak crying, the parent is most exhausted, and the brain stem is most vulnerable to shaking forces.
The acronym names the features of the peak period:
- P — Peak of crying. It rises, peaks at 6–8 weeks, then falls.
- U — Unexpected. It starts and stops without obvious reason.
- R — Resists soothing. Sometimes nothing works, and it isn't because you're doing it wrong.
- P — Pain-like face. Babies look as if they are in pain even when they aren't.
- L — Long-lasting. Can go on for an hour or more.
- E — Evening clustering. Late afternoon and evening, classically.
PURPLE programmes — typically a video and leaflet given on the maternity ward — have been studied in randomised trials. They reduce parental frustration scores and, in some studies, reduce reported shaking behaviours. They are not a soothing technique. They are a context.
The single non-negotiable message that goes with all of this: if you feel yourself reaching the edge, put the baby down in a safe place — cot, Moses basket, floor with no objects nearby — and walk into another room for 5 minutes. A baby who cries for 5 minutes alone in a safe space is not harmed. A baby who is shaken can be killed or left with permanent brain injury. There is no judgement in stepping away. It is the right thing to do.
What People Call Colic
The traditional Wessel definition (the rule of threes): crying more than 3 hours a day, more than 3 days a week, for more than 3 weeks, in a baby who is otherwise healthy and feeding well. By this definition, around 1 in 5 babies has colic.
The label is misleading because it implies gut pain as the cause, and the evidence for that is thin. Studies have looked for and not found:
- Consistent gut transit differences in "colicky" vs non-colicky babies
- Consistent benefit from anti-spasmodics, simethicone, or proton pump inhibitors
- Consistent gut microbiome differences
The more honest description is that colic is the upper tail of the normal crying curve, and it resolves on the same neurological timeline as ordinary crying — by 3 to 4 months — regardless of what is tried.
A few specific things are worth excluding before assuming the answer is "wait it out":
Cow's milk protein allergy (CMPA). Around 2–3% of infants have CMPA. Suspicious features alongside crying: blood or mucus in stool, persistent eczema, poor weight gain, recurrent vomiting. A 2-week trial of dairy exclusion (hypoallergenic formula for formula-fed; maternal dairy exclusion for breastfed) under midwife or GP supervision is reasonable.
Lactose overload (not lactose intolerance). In some breastfed babies, frequent shorter feeds expose them mainly to fore-milk and tip them into more frequent foamy green stools and abdominal discomfort. A breastfeeding adviser can help adjust the pattern.
Reflux symptoms that warrant treatment. Most "silent reflux" labelled in babies is actually normal physiological regurgitation. NICE guidance and Cochrane reviews are clear: routine acid suppression for crying babies has not been shown to help. Reserve treatment for babies with poor weight gain, faltering feeds, or significant respiratory symptoms.
Hair tourniquet. A stray hair (often a parent's) wrapped tightly around a finger, toe, or penis can cause sudden, persistent inconsolable crying. Always check.
Corneal abrasion. Same picture — sudden onset of inconsolable crying. Look at the eyes for redness or excess tearing.
Soothing Strategies That Have Some Evidence
None work every time. None work for every baby. They are options, not protocols. Harvey Karp's "5 S's" summarises the most-evidenced ones:
- Swaddling. Young infants (up to about 3 months, before they can roll). Snug enough to keep arms in but with hip room. Stop when they show signs of trying to roll.
- Side or stomach hold (in your arms only — never for sleep). Babies often calm in this position because of vestibular input.
- Shushing / white noise. Moderate volume — like a vacuum at distance, around 60–65 dB at the baby's ear. Continuous, not intermittent. Phones and apps work; so does a hairdryer or shower.
- Swinging / rocking. Rhythmic, repetitive motion. Baby in a sling against the chest is gold-standard.
- Sucking. Breast, bottle, dummy, or finger. Sucking calms the autonomic nervous system.
Beyond the 5 S's:
- Skin-to-skin. Steadies heart rate, breathing, and cortisol.
- Going outside. Fresh air, change of scenery, a walk in the carrier or pram. Often resets a stuck cycle.
- A bath. Warm water in your arms, not deep, not for long.
- Tag-teaming. When one parent is at the end, another adult takes over for 15 minutes if at all possible.
When to Seek Help
Crying that is in keeping with the curve above does not need a doctor. Crying that breaks the pattern does:
Same-day GP / NHS 111:- Sudden change to inconsolable crying that is not the usual pattern
- Crying with fever (≥38°C in under 3 months always; ≥39°C 3–6 months)
- Crying with vomiting, especially green vomit
- Crying with a non-blanching rash
- Crying with a weak or absent suck, floppiness, or reduced responsiveness
- Crying with breathing difficulty
- Inconsolable for hours despite all the usual measures, in a baby who normally settles
- Suspected hair tourniquet, sore eye, or trauma you can't identify
For parental wellbeing, also worth a call: any time crying is making you feel desperate, hopeless, or worried you might harm the baby. This is a recognised crisis, not a personal weakness, and there are services specifically for it. Health visitor, GP, NHS 111, or in genuine crisis the Samaritans (116 123) and Cry-sis (08451 228 669, daily 9am–10pm) can help.
The two facts to hold onto in the worst hours:
- The curve will fall. By 3 to 4 months, the peak passes.
- Putting a safe baby down and stepping out of the room is the right thing to do, every time, when you feel you might lose control. There is no version of that decision that is wrong.
Key Takeaways
Crying follows a developmental curve that surprises most first-time parents. It rises from birth, peaks around 6 to 8 weeks at an average of 2 to 3 hours a day, and tapers through the rest of the first year. About 1 in 5 babies will cross the 3-hours-a-day mark — the old definition of colic — and they're not broken. The pattern shows up across cultures and feeding methods, which means it isn't caused by anything you're doing wrong. The most important message: when nothing soothes them, it's the brain maturing on its own schedule, not a parental failure. Put the baby down somewhere safe and step out of the room before you snap. It is never okay to shake a baby.
