Why do infants cry so much?
Crying is an infant's primary and main mode of communication. Before speech develops, crying is how a baby signals their needs, discomfort, or distress. For a parent, especially when very tired, deciphering these cries can sometimes be a challenge. Understanding the mechanisms behind these expressions allows for a calmer and more effective response.
From a neurological perspective, a newborn is born with an immature nervous system. Their prefrontal cortex — the area of the brain responsible for emotional regulation — is still very undeveloped. This means the baby is unable to self-soothe when faced with uncomfortable stimuli. They are entirely dependent on the adults around them to return to a state of calm. This is not a tantrum: it is a biological reality documented by developmental neurosciences.
The main causes of crying in babies
There isn't a single universal framework for interpreting an infant's cries. Each baby is different, and the same cries can mean different things depending on the context. However, some causes are frequently observed.
Hunger
This is the most common cause, especially in the first few weeks. A newborn has a very small stomach capacity and digests quickly, which means frequent feedings—every two to three hours on average. Intense crying accompanied by sucking movements, head turning, or bringing hands to the mouth are often hunger signals.
Physical discomfort
A soiled diaper, an uncomfortable position, excessive heat, or clothes that are too tight can cause crying. It's useful to perform a methodical check before considering other causes. An infant who cries after feeding may be suffering from gas or gastroesophageal reflux (GER), a common situation at this age.
Need for contact and reassurance
Babies have a fundamental need for physical contact. This is not a weakness or a "bad habit": it is rooted in the evolution of the species and validated by attachment research initiated by John Bowlby. Holding the baby, gently rocking them, or simply placing a hand on their belly can be enough to soothe them. Secure attachment theory, now widely accepted in developmental psychology, shows that responding to a baby's needs builds their trust in others — and thus their future autonomy.
Fatigue and overstimulation
An overstimulated baby — too much noise, light, interaction — may cry to signal that they need calm. Paradoxically, an overly stimulating environment can prevent an infant from falling asleep, creating a cycle of fatigue and crying. Creating a calm and uncluttered play space, in line with Montessori pedagogy, can help reduce this overstimulation. The Treelys play mat is designed with this in mind: age-appropriate stimulation, without sensory overload.
Infant colic
Colic involves episodes of intense, unexplained crying in an otherwise healthy baby. According to pediatrician Morris Wessel's "rule of three" definition, colic is when crying lasts more than three hours a day, more than three days a week, for more than three weeks. It affects about 20% of infants, according to data from the French National Authority for Health (HAS), and usually disappears around 3 to 4 months of age. Its exact cause remains poorly understood.
How to respond to your baby's cries
There's no magic formula, but several validated approaches can help.
Stay calm yourself
Parental stress is perceptible to infants. Babies are extremely sensitive to their parents' tone of voice, postures, and breathing. Taking a few seconds to breathe deeply before picking up your baby is not a luxury—it's an effective strategy. If you're too tired, it's perfectly acceptable to safely put the baby in their crib for a few minutes to regain your composure.
Recognized soothing techniques
Several techniques are documented to calm crying: regular rocking (which mimics movements felt in utero), white noise (which imitates the sound of the uterine environment), skin-to-skin contact, physiological babywearing in a wrap or ergonomic carrier. American pediatrician Harvey Karp popularized the "5 S's" method (Swaddle, Side/Stomach position, Shush, Swing, Suck), some elements of which have been studied with encouraging results, although the quality of studies varies.
Maintain a predictable routine
Infants are reassured by repetition and predictability. A regular sequence around bathing, feeding, and bedtime helps the baby anticipate what's coming, thus reducing their anxiety level and the frequency of crying at the end of the day.
Excessive crying: when to worry?
The vast majority of infant crying is normal and does not indicate any pathology. However, certain signs should prompt immediate consultation with a doctor or pediatrician.
Signs that require medical consultation
Consult without delay if your baby exhibits unusual crying accompanied by fever (rectal temperature above 38°C in a baby under 3 months), a high-pitched and unusual cry, refusal to suckle or drink, projectile or repeated vomiting, a bulging fontanelle, paleness or bluish skin discoloration, or unusual lethargy. These symptoms may indicate an infection, intestinal obstruction, or other conditions that require urgent medical evaluation. In case of doubt, call 15 (emergency medical service), 3114 (national suicide prevention number, also used for intense parental distress) or your pediatrician—they are your best contacts.
Shaken baby syndrome: a crucial warning
Violently shaking a baby to make them stop crying can cause severe, even fatal, brain damage. This is a documented medical reality. Santé publique France and the Ministry of Health regularly conduct awareness campaigns on this subject. If you feel you are losing control, safely put your baby down, leave the room for a few minutes, and call a loved one or 3114. Asking for help is never a sign of weakness.
Parental support: you are not alone
Persistent infant crying can exhaust even the strongest parents. Fatigue, isolation, and feelings of incompetence are realities many families experience. Talking to your general practitioner, midwife, PMI (Maternal and Child Protection center), or a parenting support association can make a real difference. The Ameli.fr website and your local PMI services offer free resources and support.
Understanding that your baby's cries are not a criticism of your parenting skills is often the first step. You are responding to your child's needs: this is precisely what attachment science identifies as the foundation of healthy development. This period is intense, but it passes.
To learn more about the daily challenges of life with a young child, you can also consult our article on parental mental load or our dossier on baby blues and postpartum depression.
