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A growth crisis is a stage of rapid brain and body development. The first one happens at 4–6 weeks. Your baby begins to see, feel, and understand more — and this can lead to clinginess, fussiness, frequent feeds, and sleep disruptions. That’s normal: within days, new skills will appear — a social smile, focused gaze, first sounds. Your calm presence and support will help you both through this phase.

What’s Inside

A growth crisis is a time of intense development

During this stage, major changes happen in the baby’s brain. New neural connections form, and your baby starts perceiving the world differently. Physical growth also speeds up, and their thinking and behavior shift.

The growth crisis theory was developed by Dutch researchers Frans Plooij and Hetty van de Rijt. They found that in the first 20 months, babies go through predictable periods of change linked to brain and nervous system development.

The first growth crisis happens around weeks 4–6

Every baby develops differently, so the timing may vary. For some babies, the crisis may start as early as 3 weeks; for others, closer to 7.

It usually lasts 7–10 days, though it can be shorter or longer depending on the baby. Most intense signs last about 3–4 days.

What happens during the first growth crisis

• Physical growth speeds up. Babies may gain a bit more weight or length than in previous weeks.

• Brain development accelerates. New neural pathways form, especially in sensory areas.

• Perception improves. Babies start distinguishing contrast, focusing on objects, and recognizing simple patterns.

• The digestive system matures. Temporary tummy issues like gas or colic may appear.

• Motor skills improve. Babies begin to control head and upper body movements and may briefly hold up their head.

New skills after the first growth crisis

This stage helps your baby better interact with the world.

• Social smile: smiling in response to faces and voices.

• Focused gaze: staring at people, toys, or objects for longer periods, following movements with the eyes.

• Interest in high-contrast visuals: black-and-white patterns, stripes, and zigzags draw attention.

• Head control: your baby may lift their head while upright or during tummy time.

• More coordinated movements: arms and legs move with greater control.

• Cooing and new sounds: your baby responds to speech with sounds and expressions.

Behavior may change

• More fussiness and tears, sometimes without a clear reason.

• Restlessness and difficulty calming down.

• Stronger Moro reflex — startles more easily from sounds or motion.

• Greater need for closeness and contact.

• New curiosity — babies pay more attention to people and patterns.

• Lower tolerance for stimulation — they may tire more easily and need quiet time.

Feeding habits may change

• Cluster feeding: more frequent but shorter nursing sessions, especially in the evening.

• Increased appetite: babies may drink more milk or formula.

• Breastfeeding fussiness: they may latch, unlatch, cry, then try again.

• False hunger: sometimes they seek comfort, not food.

• Boost in milk supply: your body usually adjusts to the increased demand.

Sleep may become disrupted

Your baby may experience stress during a growth crisis, and sleep may change:

• Trouble falling asleep

• More frequent wakings

• Shorter deep sleep phases

• Changes in nap patterns — naps may be shorter or more frequent

• Greater sensitivity to noise or motion during sleep

These changes are temporary and improve as your baby adapts.

How to support your baby during this time

• 🤱 Provide contact: hold often, practice skin-to-skin, or use a sling.

• 🌙 Create a calm atmosphere: reduce loud sounds, bright lights, and overstimulation. Make sleep areas peaceful.

• 🍼 Feed on demand: don’t limit feeding — comfort nursing is normal.

• 🧶 Use calming routines: rocking, white noise, a warm bath before bed — anything that soothes.

• ❤️ Take care of yourself: ask for help, rest when you can, and remember — this is temporary.

When to talk to your pediatrician

If something feels off, check with your doctor.

Reasons to call:

• No eating for over 8 hours

• Signs of dehydration (dry mouth, few wet diapers)

• Extreme sleepiness or lethargy

• Fever, rash, strange movements, or sharp crying

Essentials for baby care many parents choose

Sources

• Plooij FX, van de Rijt-Plooij H. The Wonder Weeks: How to Stimulate Your Baby's Mental Development and Help Him Turn His 10 Predictable, Great, Fussy Phases into Magical Leaps Forward. Kiddy World Publishing; 2017. ISBN: 978-9491882166

• Hinde K, Skibiel AL, Foster AB, Del Rosso L, Mendoza SP, Capitanio JP. Cortisol in mother's milk across lactation reflects maternal life history and predicts infant temperament. Behav Ecol. 2015 Jan-Feb;26(1):269-281. doi: 10.1093/beheco/aru186. Epub 2014 Oct 31. PMID: 25713475; PMCID: PMC4309982. https://pubmed.ncbi.nlm.nih.gov/25713475/. Accessed 1 Apr. 2025.

• Fleming AS, O'Day DH, Kraemer GW. Neurobiology of mother-infant interactions: experience and central nervous system plasticity across development and generations. Neurosci Biobehav Rev. 1999 May;23(5):673-85. doi: 10.1016/s0149-7634(99)00011-1. PMID: 10392659. https://pubmed.ncbi.nlm.nih.gov/10392659/. Accessed 1 Apr. 2025.

• Douglas PS, Hill PS. Behavioral sleep interventions in the first six months of life do not improve outcomes for mothers or infants: a systematic review. J Dev Behav Pediatr. 2013 Sep;34(7):497-507. doi: 10.1097/DBP.0b013e31829cafa6. PMID: 24042081. https://pubmed.ncbi.nlm.nih.gov/24042081/. Accessed 1 Apr. 2025.

• Barr RG, Trent RB, Cross J. Age-related incidence curve of hospitalized Shaken Baby Syndrome cases: convergent evidence for crying as a trigger to shaking. Child Abuse Negl. 2006 Jan;30(1):7-16. doi: 10.1016/j.chiabu.2005.06.009. Epub 2006 Jan 6. PMID: 16406023. https://pubmed.ncbi.nlm.nih.gov/16406023/. Accessed 1 Apr. 2025.

• Ball HL. Breastfeeding, bed-sharing, and infant sleep. Birth. 2003 Sep;30(3):181-8. doi: 10.1046/j.1523-536x.2003.00243.x. PMID: 12911801. https://pubmed.ncbi.nlm.nih.gov/12911801/. Accessed 1 Apr. 2025.