But does infant colic really exist? Here’s what the research says and what the experts recommend

For many years, experts have questioned the use of the word ‘colic’ to describe prolonged, inconsolable crying in newborns: this term, in fact, attributes the cause of the phenomenon to the gut, to the extent that it is often translated in everyday language as ‘tummy ache’. In reality, even today, almost seventy years after it was first described, it is still not entirely clear what causes an infant – particularly in the evening and during the first three months of life – to cry for hours on end, with nothing able to soothe them. It has therefore been decided to replace the term ‘colic’ with the more generic ‘Infant Distress Syndrome’. This is the term proposed by the new Rome V guidelines – updated, that is, to the fifth edition – published by the Rome Foundation, an international organisation of experts that studies disorders linked to the interaction between the gut and the brain.

The new guidelines not only change the name of infant distress syndrome, but also the criteria for diagnosing it. Until now, in fact, infant colic has always been defined using the ‘rule of three’ established in the early 1950s by an American paediatrician: the definition required a baby to start crying for at least three hours a day, for at least three days a week, for at least three consecutive weeks, before the age of three months. Owing to its simplicity, this formula proved very successful, but it was clearly too restrictive for a condition that can vary in nature yet often has a significant impact on a family’s peace of mind. For this reason, it has now been decided that infant distress syndrome can be diagnosed when a baby, before reaching five months of age, begins to cry or become agitated for long periods for no apparent reason, with episodes that recur over time and which the parents are unable to prevent or resolve in any way. The clarification ‘for no apparent reason’ is important, as there may be medical conditions causing the baby to become agitated in this way. Before a diagnosis of infant distress syndrome is made, the paediatrician must therefore have ruled out other possible causes of the distress.

We do not yet know for certain what causes infant distress syndrome, which is why the term ‘colic’ – which suggested intestinal problems – has been abandoned. In the past, it was thought that the discomfort stemmed from air in the tummy or from gastric acid reflux from the stomach into the oesophagus, but neither of these theories has stood up to the scrutiny of controlled trials testing the effectiveness of specific medicines which, had these been the causes, should have provided relief. An interesting line of research concerns the composition of the gut microbiota, which in these boys and girls may be more uniform, with a lower variety of microorganisms, compared to that of their peers who do not suffer from ‘colic’. Supporting this interpretation are studies showing some benefit from the administration of certain probiotics – that is, live bacterial strains thought to have a beneficial effect on the gut – but these findings require further confirmation.

Another line of research focuses on the nervous system of the infant, which, after birth, must develop the ability to regulate internal stimuli such as hunger and thirst, heat and cold – all of which were unknown whilst in the womb – but also to adapt to external stimuli, such as lights, noises that are no longer muffled, movements and different environments. The calm demeanour of the adult who picks the baby up, rocks them, whispers to them or sings lullabies can help them to settle, whilst, conversely, tiredness, anxiety and nervousness can trigger a negative vicious circle.

First and foremost, when a baby – whether a boy or a girl – who is not yet able to express their needs starts crying, you should check that they are not in pain anywhere, is hungry or thirsty, too hot or too cold, has a soiled nappy, or is being overstimulated by their surroundings (for more information, read the factsheet ‘Should I be worried if my newborn is crying?’).