Health

New Research Finds That Established Beliefs About Infant Crying Might Not Be True

Newborn Baby Crying

A new study challenges what is thought to be the normal pattern of crying, the “cry curve” to which parents are presently often referred to.

The study provides a new understanding of what constitutes normal and excessive crying among infants

When will my baby stop crying so much?

Study shows that the intensity and duration of infant crying do not peak after five weeks which contradicts the “cry curve” that has been widely used for many years, says associate professor Christine Parsons. Credit: AU Health

If you are a new parent who googles this question in a sleep-deprived state, the answer may comfort you.

Many top Google results will direct you to an outdated study that concludes that newborn crying often peaks around the age of six weeks, then drops significantly and stabilizes at a low level after three months.

Parents may anticipate their newborns to cry much less following the initial peak, which is often referred to as the “cry curve.” A recent Danish study, however, questions this “cry curve” pattern by combining data from parents in 17 different nations.

“We’ve created two mathematical models that reasonably represent the available data. Neither of them shows that the duration of crying falls so markedly after five weeks, which is what is otherwise seen in the graphs that are presented to parents. The available data shows that crying is still a significant part of many infants’ repertoire after six months,” says Christine Parsons, who is an associate professor at the Department of Clinical Medicine at Aarhus University.

Widely used cry curve

The researchers behind the study have compiled data from 57 research articles from all over the world, in which parents have registered how much their infants cry every day.

The normal pattern of crying, the “cry curve” to which parents are presently often referred to, is based on an American study from 1962, which only focuses on the first twelve weeks of a child’s life.

“It’s a graph that new parents are often presented with. If you google ‘infant crying’ you’ll see lots of images of this particular graph. Therefore, we thought it would be interesting to model all the available data to see what type of pattern best represents the data, and test if this is consistent with the original ‘cry curve’,” says Arnault-Quentin Vermillet, the first author of the article.

An important tool for clinicians

Crying is one of the first forms of communication used by infants to get their parents’ attention. The infant’s cognitive and emotional development is stimulated when parents react to the child’s signals appropriately.

New parents often seek help from the healthcare system if they are worried that their child is crying too much.

According to Christine Parsons, it is therefore important that both healthcare professionals and parents have a correct and precise understanding of normal patterns of crying for infants.

“For clinicians in particular, it’s important because their job is to help, support, and reconcile the expectations of any worried parents. It’s important that clinicians have up-to-date data on what is normal for infant crying so that they can best support new parents. When parents consider their child to cry excessively, this can be associated with negative consequences for both parent and child,” she explains.

Cry patterns vary a lot

A widely-used definition for excessive crying, or colic, is when a baby cries for more than 3 hours per day, more than 3 days over a week. In the first 6 weeks after birth, colic has been estimated as affecting between 17 and 25% of infants.

The researchers at Aarhus University have drawn up two new models for the infant cry pattern. One of them shows infant crying peaks after four weeks. The other shows that infants cry a lot and at a stable level during the first weeks, after which the level falls.

However, neither model indicates a steep decline, as otherwise appears to be the case from the “original cry pattern”.

According to Christine Parsons, another noteworthy finding in the study is how different crying patterns are among babies– both within and across national borders.

As an example, she mentions that the limited available data indicates children from non-Western countries such as India, Mexico, and South Korea, cry less than children from English-speaking countries such as the United States, Great Britain, and Canada.

Reference: “Crying in the first 12 months of life: A systematic review and meta-analysis of cross-country parent-reported data and modeling of the ‘cry curve'” by Arnault-Quentin Vermillet, Katrine Tølbøll, Samouil Litsis Mizan, Joshua C. Skewes and Christine E. Parsons, 19 April 2022, Child Development.
DOI: 10.1111/cdev.13760

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  • Any study that ignores the differences between boy and girl infants can be dismissed. We also know that parents pay significantly less attention to boy infants when they cry, which in turn affects when and how much boy infants cry in future. You need to incorporate this.

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Aarhus University

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