Baby Won't Stop Crying: Understanding PURPLE Crying and Colic
Your baby crying doesn't mean you're a bad parent It's a normal developmental phase that will pass — and never, ever shake your baby.
A baby who won't stop crying can leave new parents feeling exhausted, helpless, and questioning everything. But the truth is: heavy crying in the first 2–5 months is a normal developmental phase, not a sign you're doing anything wrong.
This article draws on AAP [1] [2], the National Center on Shaken Baby Syndrome [3], and the Royal College of Pediatricians of Thailand [4] to help parents get through the hardest stretch of early parenting.
What is PURPLE Crying?
PURPLE Crying is a term coined by researcher Dr. Ronald Barr to explain why what looks like "abnormal" crying is actually a normal developmental phase that every baby goes through [3].
What each letter stands for
- P — Peak of crying — crying peaks around 2 months of age, then gradually decreases from 3–4 months
- U — Unexpected — crying starts and stops for no clear reason
- R — Resists soothing — hard to comfort; nothing seems to work consistently
- P — Pain-like face — baby looks like they're in pain, but they're not
- L — Long-lasting — can last up to 5 hours in a day
- E — Evening — tends to happen most in late afternoon and evening
Why does it happen?
- Immature nervous system — a developing brain that's still learning to regulate
- Not the parent's fault — not a sign that something is wrong with your baby
- Resolves on its own by 4–5 months
Colic — the Rule of 3s
Colic is a more specific diagnosis than PURPLE Crying. Per AAP criteria [2]:
- Crying for more than 3 hours per day
- On at least 3 days per week
- For at least 3 weeks in a row
- In an otherwise healthy baby who feeds and grows well
Colic affects roughly 20% of babies and typically resolves on its own by 3–4 months. The exact cause is not fully understood — current theories include:
- Immature digestive system
- Sensitivity to cow's milk protein in some babies
- Immature nervous system
- Overstimulation from the environment
Soothing your baby — Dr. Harvey Karp's 5 S's
The approach recommended by AAP [1] that mimics the "fourth trimester" — the womb environment your baby knows:
1. Swaddle (wrap snugly)
- Wrap baby firmly so they feel warm and secure
- Wrap the torso and arms only — legs must be able to move freely
- Stop swaddling when baby starts rolling over (usually 4–6 months) — reduces SIDS risk
2. Side or stomach (for soothing only)
- Hold baby on their side or stomach against your chest
- Only while awake and being held — always place baby on their back to sleep
- This position helps calm most babies quickly
3. Shush (white noise)
- Make a sustained "shhhh..." sound close to baby's ear
- Mimics the sounds inside the womb — louder than you'd expect
- A white noise machine, app, or even a running washing machine works well
4. Swing (gentle motion)
- Gently rock baby in your arms
- Never shake — even gently — there is no safe shaking. What's meant here is a small, slow, rhythmic sway
- Gentle motion replicates the movement baby felt while you walked during pregnancy
5. Suck (sucking reflex)
- Offer the breast, a clean finger, or a pacifier
- Sucking has a calming effect on the nervous system
- Introduce a pacifier after breastfeeding is well established (3–4 weeks)
Other techniques that help
- Baby wrap or carrier — warmth and constant gentle motion
- Warm bath — relaxing for both baby and parent
- Change the environment — step outside for fresh air and a change of scenery
- Gentle tummy massage — may help if gas is a factor
- Car ride — the vibration and motion soothes many babies
- White noise — app, fan, vacuum cleaner in another room
- Back to basics — run through the checklist: hungry? wet diaper? too hot or cold?
Taking care of yourself
This is just as important — taking care of yourself is taking care of your baby:
When you feel at your limit
- Put baby down in a safe place (crib or bassinet) and step out of the room for 5–10 minutes
- Breathe deeply, drink some water, eat something
- Call your partner, family, or a friend — ask for real help
- A baby crying in a safe crib is not in danger
- Never shake your baby [3] — Shaken Baby Syndrome causes permanent brain damage or death
Shaken Baby Syndrome (SBS) — the most important thing here
- Never shake your baby — no matter how exhausted you are
- Babies have weak neck muscles and fragile, developing brains
- Shaking for even a few seconds can cause:
- Brain hemorrhage
- Blindness
- Permanent disability
- Death
- If you feel you've reached your limit → put baby down, walk away, call for help
Finding support
- Tell your partner when you genuinely need a break
- Ask family — grandparents, siblings — for real help
- Join a parent group — local, online, or on social media
- Talk to your doctor about postpartum depression — it's real, common, and treatable. Don't wait.
When to see a doctor immediately
- Crying + fever ≥ 38°C in a baby under 3 months — this is an emergency
- Cry sounds different — unusually high-pitched or hoarse
- Baby is unusually lethargic or difficult to wake
- Green vomiting — possible intestinal obstruction
- Noticeably swollen or hard abdomen
- Not gaining weight or losing weight
- Eating significantly less for more than 24 hours
- Very few wet diapers — sign of dehydration
- Any unexplained bruising or marks on the body
Summary
Heavy crying in the first 2–4 months is normal — it is not your fault.
Key principles:
- PURPLE Crying is a normal developmental phase that will resolve on its own
- Try the 5 S's — swaddle, side, shush, swing, suck
- If you're overwhelmed, put baby in a safe place and take a short break
- Never shake your baby — Shaken Baby Syndrome is life-threatening
- Ask for help from those around you — it's not a sign of weakness
- See a doctor immediately if baby under 3 months has a fever, or if anything seems medically wrong
By 4–5 months, this phase of heavy crying will gradually fade. Until then: be patient, be kind to yourself. Every parent gets through it.