Crying Durations in Infantile Life: Colic’s Cut-off Point​
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Crying Durations in Infantile Life: Colic’s Cut-off Point
Jack Hunter
Student of William & Mary
Abstract
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Colic originates from kolikos, a Greek word which means “abdominal pain”. Despite this,
it is unclear whether infantile colic, a syndrome characterized by excessive crying, is caused by
abdominal pain. Early studies like Wessel et al. (1954) tend to categorize colic as a behavioral
condition, similar to labeling a child as overly-fussy. But there is currently no objective
pathology for infantile colic. The proposed study uses video/audio recording to capture crying
durations during the first twelve weeks of life. We predict that infantile crying durations between
participants will have an abnormal distribution, potentially attributable to colic.
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Keywords: Crying, fussy, colic, infants, tantrum
Introduction
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Infantile colic (referred to as colic throughout this paper) is a behavioral condition
characterized by bouts of excessive crying during the first three months of an infant’s life. It is a
common source of parental concern, affecting ~20% of the infant population (Kaley, Reid, &
Flynn, 2011) (Wolke, Bilgin, & Samara, 2017). Colic is not associated with negative long-term
outcomes for infants (Kaley, Reid, & Flynn, 2011), but the distress it inflicts upon caregivers can
strain familial relationships. In this way, it is unclear whether colic is meant to identify infant
distress or parental distress.
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In early psychological studies, colic is used synonymously with “fussiness” (Wessel et al.
1954). Loose behavioral observations identified and separated problematic babies from the
general population. Modern studies use crying durations as a more objective measure of
fussiness (Kaley, Reid, & Flynn, 2011) (Vermillet et al., 2022). Colic is often identified through
Wessel’s “rule of three”, which states that an infant must cry for at least three hours a day for
three days each week during a period of three weeks or longer (Wessel et al., 1954). However,
this definition lacks the distinctive behavioral symptoms that would be needed to differentiate
colic as a unique ailment. It also lacks empirical evidence. As a result, Wessel’s rule is not
universally accepted by researchers or clinicians (Kaley, Reid, & Flynn, 2011). As of the date of
this study, no viable alternatives for identifying colic have been proposed. As a result, it is
primarily used by clinicians as a diagnosis by exclusion (Kaley, Reid, & Flynn, 2011).
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The inconclusive nature of colic complicates its pathology. Speculations on the nature of
colic can be sorted into four categories: environmental, physiological, both, and neither (Kaley,
Reid, & Flynn, 2011). In the environmental approach, colic is synonymous with fussiness.
Excessive crying behavior arises from a kid’s surroundings and can be treated with behavioral
interventions. On the other hand, the physiological approach solidifies colic as a medical
condition. There are many theoretical causes, but the only one with empirical support is milk
allergies causing infantile gastrointestinal distress, resulting in crying (Kaley, Reid, & Flynn,
2011). The connection between lactose intolerance and colic is further supported by the fact that
dietary interventions have proven mildly effective against certain colic populations (Kaley, Reid,
& Flynn, 2011). But in general, colic is a blanket term without conclusive evidence for a specific
cause or treatment.
A lot of research has been done on crying - the main symptom of colic. Vermillet et al.
(2022) performed a meta-analysis that synthesized studies involving parent-reported cry
durations. The meta-analysis sampled 7,580 infants from 57 studies published between 1986 and
2020. Studies had varying durations and designs. The median cry duration over the first year of
birth was found to be 126 minutes (SD = 61). Crying behavior was also found to be highest
during the first six weeks of life, after which it experiences a gradual decline. These results are
supported by Wolke, Bilgin, & Samara (2017), another meta-analysis of crying literature. This
study sampled 8,500 infants from 28 studies. The mean fuss/cry duration over the first six weeks
fell between 117 and 233 minutes (p = 0.05). Using the Wessel rule (~180 minute cutoff), colic
was found to have a 17-23% prevalence. This distribution suggests that some, if not all colic can
be explained by typical variation in infant crying durations. Colic infants may just be on the
higher end of normal crying behavior.
However, Vermillet, A. Q. et al. (2022) and Wolke, Bilgin, & Samara (2017) draw from a
diverse pool of international research. Differing study methodologies and sample groups
introduce a lot of variance. Additionally, both studies used 24 hour diaries as the main measure
for capturing cry/fuss data. These parent journals are more reliable than retrospective surveys,
but they still contain some inaccuracies. This is because memory biases are known to cause
between-participant variation in cataloguing infant crying. When compared to audio recordings,
baby diaries have a correlation of 0.67% (Barr, 1998). Many studies repurposed for these
meta-analyses also revolve around short periods of infancy. A lack of long-term cry studies
complicates attempts to define a “normal” amount of fussiness. With these flaws in mind, it
becomes clear that colic research requires more general studies on normal cry duration.
Method
At least 200 newborns will be recruited through community advertisements targeting
postpartum parents. Participation will be incentivized through a free year-long subscription to
Colic’s Cut-off Point​
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Bibino: a baby monitoring app. Research will also be conducted through this app. Caretakers will
be instructed to capture one 24 hour video/audio recording of their child during each of the first
twelve weeks of infancy. To avoid privacy concerns, participants are free to temporarily stop the
recording at any point in time.
This creates a dataset of twelve 24-hour recordings for each infant. Each of these
recordings will be put through facial recognition and audio processing software in order to
automate the annotation process. These programs will sort footage of the infants into two groups:
calm and fussing/crying. In order to ensure accuracy, researchers will watch a few minutes of
each labeled video recording with audio to ensure the accuracy of the software.
Predictions
We predict that changes in mean infant crying duration over the first twelve weeks will
reflect the findings of Vermillet, A. Q. et al. (2022) and Wolke, Bilgin, & Samara (2017). Crying
duration will remain high for the first six weeks, then steadily decline. Infants cry the most
during the sixth week of infancy, though this peak may not be significantly higher than the first
five weeks of infancy.
Figure 1. Mean crying duration among the first 12 weeks of infancy. Duration remains stable during the
first six weeks, experiences a slight decline over the next three weeks, then remains stable for the
remaining quarter. Crying duration peaks at 155 min at six weeks. Missing data (gaps in Bibino
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recordings) and outliers have not been factored into the mean. Infants diagnosed with crying disorders
other than colic are also not included.
Figure 2. Distribution of crying duration during week 6 of infancy. Bimodally distributed. A large bell
curve lags slightly behind the mean, while the smaller one peaks around 220 minutes.
More importantly, a significant bimodal distribution in cry duration, especially during the
first few weeks, would be relevant to colic. If the distribution for natural sleep variation does not
fall into a bell curve, it is probable that a confounding variable is involved. This circumstantially
supports the physiological theory of colic. Clean data on the duration of infant crying is also a
good foundation for a more scientific cut-off point for colic, providing an alternative to the
Wessel “rule of three”.
Conclusion
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Colic is a condition plagued with unknowns. It has no clear cause or treatment, which
creates a lot of distress for parents raising a colic infant. Though colic is associated with no
negative outcomes, research on crying behavior would reassure the nerves of infants and parents
alike. Additionally, colic is at least partially tied to parental wellbeing. Distressed parents are
more likely to visit clinicians and push for a diagnosis. A dataset of average crying durations
makes it easier to identify pathological crying syndromes.
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References
Barr, R. G., Kramer, M. S., Boisjoly, C., McVey-White, L., & Pless, I. B. (1988). Parental diary
of infant cry and fuss behaviour. Archives of Disease in Childhood, 63(4), 380-387.
https://doi.org/10.1136/adc.63.4.380
Kaley, F., Reid, V., & Flynn, E. (2011). The psychology of infant colic: A review of current
research. Infant Mental Health Journal, 32(5), 526-541. 10.1002/imhj.20308
Vermillet, A. Q. et al. (2022). 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”.
Child Development, 93(4), 1201-1222. 10.1111/cdev.13760
Wessel, M. A. et al. (1954). Paroxysmal fussing in infancy, sometimes called" colic". Pediatrics,
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Wolke, D., Bilgin, A., & Samara, M. (2017). Systematic review and meta-analysis: fussing and
crying durations and prevalence of colic in infants. The Journal of Pediatrics, 185, 55-61.
10.1016/j.jpeds.2017.02.020