OBJECTIVE. To report the prevalence and stability of cry-fuss problems during the first 4 months of life and sleep problems from 2 to 24 months and relationships between the persistence of cry-fuss and sleep problems and outcomes at 24 months.
METHODS. The study was a prospective cohort study in maternal and child health centers in 3 local government areas in Melbourne, Australia. A total of 483 first-born infants were monitored prospectively from 2 weeks through 2, 4, 8, 12, 18, and 24 months. Child behavior, maternal depression, parenting stress, and marital quality were assessed. Predictor variables were parent reports of moderate or greater cry-fuss problems (2 and 4 months) and sleep problems (8, 12, 18, and 24 months) and parent-reported, 24-hour, sleep/cry-fuss diaries (2, 4, and 12 months).
RESULTS. The response rate was 68% (483 of 710 infants); the attrition rate was <6%. The prevalence of cry-fuss problems decreased from 19.1% at 2 months to 12.8% at 4 months, with 5.6% of mothers reporting cry-fuss problems at both ages. Prevalence rates of sleep problems were 21.2%, 16.2%, 10.0%, and 12.1% at 8, 12, 18, and 24 months, respectively; 6.4% had a problem at ≥3 of these ages. In multivariate analyses, cry-fuss/sleep problems at ≥3 previous time points (but not 1 or 2 time points) contributed significantly to depression (2.8% of variance), total behavior (1.4% of variance), and total stress (4.6% of variance) scores. Repeated problems had a greater impact than a concurrent sleep problem on depression and stress scores, whereas the reverse was true for behavior scores.
CONCLUSIONS. Most cry-fuss and sleep problems in the first 2 years of life are transient. Persistent, rather than transient, problems contribute to maternal depression, parenting stress, and subsequent child behavior problems.
Sleep and cry-fuss problems are among the most common (and therefore economically costly1) difficulties reported by parents of young children. Depending on the definitions used,2 the prevalence of cry-fuss problems (often referred to in the literature as “colic”) among infants <6 months of age varies from 5% to 28%3 and is reported variably to peak somewhere between 3 and 6 weeks of age.3–5 In a large cross-sectional study, the prevalence rates of sleep problems were reported to be 23%, 27%, 36%, 36%, 28%, and 32% at 1 to 3, 4 to 6, 7 to 9, 10 to 12, 13 to 18, and 19 to 24 months of age, respectively.6
Evidence regarding the stability and persistence of cry-fuss and sleep problems in early life is mixed. Strong correlations have been noted in the amounts of actual time spent crying-fussing throughout the first year of life,7 with suggestions that excessive crying may be attributable to stable temperament-like characteristics.8 However, several researchers have noted considerable movement into and out of “colic” and cry-fuss groups. One study9 found significant intraindividual variability in crying and fussing/fretting behavior between 0 and 5 months and between 5 and 10 months of age, but the behavior was more stable by 10 to 15 months. In another study,3 of the 35 infants with “colic” identified at 3 months of age, 18 infants had colic at 6 weeks and 17 did not have colic at 6 weeks. In a study of children with a parent-defined sleep problem at 8 months of age, only 32% were still reported as having a sleep problem at 3 to 4 years of age.10 Similarly, it was reported that 41% of children meeting criteria for a sleep problem at 8 months of age still had a problem at 3 years of age, whereas 26% of children without a problem at 8 months had developed a problem by 3 years.11
A number of studies have implicated cry-fuss and/or sleep problems in immediate and later parent and child difficulties. Maternal depression was associated with both cry-fuss4 and sleep problems10,12 in cross-sectional studies. In a review of 12 longitudinal studies examining outcomes of infant colic, Lehtonen13 noted that several studies raised some concerns, with Stifter and Bono,14 for example, reporting that mothers whose infants had a cry-fuss problem at 3 to 5 weeks of age scored lower on a maternal self-efficacy questionnaire at 5 months and Rautava et al15 reporting that colicky 3-month-old infants were reported to have more frequent temper tantrums at 3 years of age. Overall, however, Lehtonen13 concluded that “most infants with colic have good prognoses for normal physical, cognitive, and behavioral development.” Although overall the research can be interpreted as reassuring, there are some weaknesses with this literature. Most relevant to this article, typically studies categorized subjects into 2 mutually exclusive groups (problem versus no problem), somewhat at odds with the suggestion that these clinical features may be rather fluid over time (see above) and precluding the examination of outcomes as they relate to the developmental trajectories of cry-fuss and sleep problems.
The Parent Education and Support (PEAS) program was a community-based longitudinal study of 483 first-born infants who were monitored intensively with questionnaires and diary reports throughout the first 2 years of life. Therefore, we were able to study the prevalence and stability of cry-fuss problems over the first 4 months of life and the prevalence and stability of sleep problems from 8 to 24 months of age. PEAS also provided an unusual opportunity to study at 24 months of age parent and child outcomes of infant cry-fuss and sleep problems in the first 2 years of life.
The sample included first-time mothers in 3 local government areas (LGAs) of Melbourne (population: 3.3 million), Australia. The 3 LGAs, with a mean annual birth rate of ∼1350 births per year per LGA, were selected from Melbourne's 31 LGAs to provide a broad sociodemographic range of families from urban, suburban, and semirural areas. Mothers were approached by community-based maternal and child health nurses, who provide a universally available, scheduled, developmental and health service to all preschool-aged children; maternal and child health nurses successfully home-visit 96% of all mothers within 2 weeks after a birth, and 98% of mothers participate in the service in the first 1 year of life.16 All nurses in the 3 LGAs were asked to approach first-time mothers sequentially in the first 2 postpartum weeks, between June 1998 and February 1999 (group 1) and between July 1999 and February 2000 (group 2), with a view to recruitment by the research team. The study was approved by the Royal Children's Hospital Ethics in Human Research Committee, and written informed consent was obtained from all participating mothers.
The PEAS program began as a prospective, before/after, nonrandomized study incorporating brief, standardized, universal or secondary prevention approaches to common problems experienced by many first-time parents in the first 2 years of their child's life. Mothers in group 1 constituted the control group, whereas mothers in group 2 received PEAS interventions in addition to the standard maternal and child health service. Cry-fuss and sleep were 2 of the conditions targeted for brief universal anticipatory guidance with the intervention group (see Web site for a full report of the PEAS interventions).17 At the scheduled 4-week visit and at a first-time parent group session, maternal and child health nurses were asked to discuss crying, fussing, and settling in a standardized way and to give parents a supporting information leaflet provided by the researchers. At the 4- and 8-month scheduled visits, maternal and child health nurses briefly discussed infant sleep and provided specifically written, brief, anticipatory guidance notes about nighttime sleep routines and simple strategies to encourage good sleep patterns.
Data were collected via 7 written questionnaires mailed to participating mothers at 2 weeks and 2, 4, 8, 12, 18, and 24 months. This article draws on cry-fuss and sleep data from each time point and parent and child outcome data at 2 years.
Parents completed global 5-point ratings of the extent to which their child's crying-fussing was a problem at 2 and 4 months, with an identical question about sleep at 8, 12, 18, and 24 months. At each time point, responses were dichotomized into “problem” (very large, large, or moderate problem) and “no-problem” (small or no problem) groups, to enable examination of changes in group membership over time as a repeated measure.18 At 2, 4, and 12 months, parents also completed a single, 24-hour, infant sleep/fuss diary, as developed originally by Barr et al.19 Sleeping, feeding, awake/content, and cry-fuss periods were recorded at 5-minute intervals over a single 24-hour period (8:00 am to 8:00 am).
Outcomes at 2 Years
Maternal postnatal depression was measured with the 10-item Edinburgh Postnatal Depression Scale (EPDS); of a possible maximal score of 30, scores of ≥10 are considered indicative of depression in a community sample.20,21 Behavior was assessed with the 99-item Child Behavior Checklist (CBCL/2–3), which was used as an outcome measure in previous studies of sleep problems.10 Total, externalizing, and internalizing scores were calculated. The 36-item Parenting Stress Index (PSI) Short Form is a validated measure of stressors related to dysfunctional parenting, yielding a total score and 3 scale scores (parental distress, parent-child dysfunctional interaction, and difficult child). With the global single item from the Dyadic Adjustment Scale (DAS), parents rated on a 7-point scale their overall relationship happiness (“extremely unhappy” to “perfect”). This item correlates strongly with total DAS scores and predicts well-adjusted versus distressed relationships reliably.22
The accuracy of parent questionnaires was determined through direct verification of a random selection of 2% of all questionnaires, yielding a 0.15% error rate, which was deemed satisfactory. One researcher entered all completed daily diaries into RonNicLog, a program designed for analysis of the repeated-measures diary data. Six months after all diaries were entered, we selected randomly 1 of the 3 diaries to be reentered by the same researcher for a randomly selected 10% of participants, with an error rate of <1%.
Because the overall findings were similar for the 2 groups (see below), we combined the intervention and control groups for all subsequent analyses. To compare problem and no-problem groups at each time point, we used χ2 tests for categorical data and Mann-Whitney U tests for continuous data; for all 2-group correlations between continuous variables, Spearman's r is reported. Three separate regression models using the enter method were constructed to examine the amount of independent variance in 24-month EPDS, PSI, and CBCL scores explained by the cumulative number of time points at which parents reported that their child had a cry-fuss and/or sleep problem. The 24-month outcome variables were logarithmically transformed to normalize the data before the regression analyses were performed. Maternal education was entered as the first covariate and then concurrent presence/absence of a sleep problem at outcome, followed by the independent variables of interest (ie, cumulative number of time points at which a cry-fuss or sleep problem was present).
Of the 710 first-time parents contacted regarding PEAS, 483 (68%) were recruited successfully (235 in the control group and 248 in the intervention group). Response rates were high (88–99%) for all 7 questionnaires, with the overall attrition rate being <6%. Demographic characteristics are shown in Table 1; it can be seen that this was largely an educated, middle-class sample. Although slightly more intervention group than control group mothers reported that their child cried less than other infants at 8 weeks (53% and 41%, respectively; χ2 = 7.2, P = .03), this was not sustained at 4 months (63% and 55%, respectively; χ2 = 1.3, P = .25). The 2 groups did not differ in parent reports of whether their child's sleeping was a problem (8 months: 16% and 17% in the intervention and control groups, respectively; χ2 = 0.04, P = .85; 12 months: 19% and 23% in the intervention and control groups, respectively; χ2 = 0.5, P = .48).
Prevalence and Persistence of Cry-Fuss and Sleep Problems
Children whose parents considered their crying to be a problem had significantly more crying bouts, had longer crying bouts, and spent more time crying each day at both 2 and 4 months (Table 2). The overall prevalence of cry-fuss problems decreased from 19.1% at 2 months to 12.8% at 4 months (χ2 = 28.9, P < .0001), with only 24 infants (5.6%) having cry-fuss problems at both 2 and 4 months. There was much movement into and out of the cry-fuss category; 55 of the 70 infants with a problem at 2 months exhibited resolution by 4 months, by which time 29 other infants had developed a “new” cry-fuss problem. Consistent with this, when the data were treated as skewed continuous variables (1 = a very large problem; 5 = no problem at all), the correlation between the severity of cry-fuss at 2 months and that at 4 months was only moderate (r = 0.48, P < .01).
Table 2 also shows that, regardless of the presence of a sleep problem, sleep bouts over time decreased in number but increased in duration, so that the total amount of sleep per day changed little throughout the first 1 year of life. The prevalence of reported sleep problems decreased from 21.2% at 8 months to 16.2% at 12 months and then plateaued in the second year (10.0% at 18 months and 12.1% at 24 months). As shown in Table 3, 66% (n = 262) of parents reported no sleep problem at any time point and most (57%) of the remaining 135 parents reported a problem at 1 time point only. Like cry-fuss problems, many children moved in and out of the sleep problem category over time. Despite this high prevalence of reported sleep problems at each time point, persistent sleep problems were rather unusual, with only 6.4% (25 of the 397 children with complete data) having a problem at ≥3 of the time points measured (Table 3). When the data were treated as continuous 5-point variables, there were moderate and consistent correlations between parent-reported sleep problems at consecutive time points (8 and 12 months, r = 0.48; 12 and 18 months, r = 0.48; 18 and 24 months, r = 0.46; all P < .01). However, the correlation between sleep problems at 8 and 24 months was rather weak (r = 0.28, P < .01), as were correlations between cry-fuss problems at 2 to 4 months and sleeping problems at 8 to 24 months (r = 0.17–0.23 across the different time points).
Outcomes at 2 Years of Age for Children With Cry-Fuss and/or Sleep Problems
Two-year parent outcomes were examined according to cry-fuss and/or sleeping problems at the various times. Table 4 shows univariate relationships between each reported problem at each time point and 24-month outcomes (EPDS, DAS, PSI, and CBCL scores), suggesting that sleep and cry-fuss problems at most preceding ages have a significant lasting impact on how parents perceive their own mental health, their relationship with their child, and their child's behavior.
Multivariate analyses suggested a rather different interpretation (Table 5). A concurrent sleep problem at 24 months accounted for 2.2% and 2.8% of the variance in total CBCL and PSI scores, respectively, at that time but did not contribute to depression scores. Earlier cry-fuss or sleep problems at just 1 or 2 time points contributed little additional variance to the model, but cry-fuss and/or sleep problems at ≥3 previous time points contributed significantly and independently to the EPDS (2.8% of variance; P = .001), total CBCL (1.4% of variance; P = .02), and total PSI (4.6% of variance; P < .001) scores. Repeated cry-fuss/sleep problems had a greater impact on 24-month EPDS and PSI scores than did the presence of a concurrent sleep problem, whereas the reverse was true for CBCL scores.
Bearing in mind that the study was conceptualized originally as an intervention study, we repeated the 3 regression models, this time entering intervention/control status before all other variables. Intervention status predicted EPDS scores at 2 years of age (1.6% of variance; P = .02), but the contribution of persistent cry-fuss and/or sleep problems to EPDS scores remained virtually unchanged (2.4% of variance; P = .003). Intervention status did not predict PSI or CBCL scores or alter the contribution of persistent cry-fuss and/or sleep problems to these outcomes.
Parent-reported cry-fuss and sleep problems were prevalent at every age between 2 and 24 months. However, although they are immediately distressing and known to be costly in terms of health care utilization, this article shows not only that the great majority of infant cry-fuss and sleep problems in the first 2 years of life are transient but also that these problems do not seem to be strongly related to later adverse outcomes. These results are both reassuring and concerning. Only ∼5% of mothers reported more persistent problems, but these were most strongly associated with poorer outcomes (especially maternal depression and parenting stress) at age 2.
Generally, these results are consistent with those of other studies but go further by virtue of the large number of reporting time points. We are not aware of any other community-based study of infant cry-fuss and sleep problems that prospectively sampled such a large number of parent/infant pairs on so many occasions throughout the first 2 years of life. Because attrition rates in this study were extremely low, we are confident of the reported internal validity of the longitudinal relationships between predictor and outcome variables.
We acknowledge several weaknesses of the study. First, the sample was largely middle class and included only first-born infants; therefore, findings may not be generalizable to other populations (although the prevalence rates reported here are consistent with those in other studies not limited to first-born infants11,12). Second, in the absence of an accepted definition of what constitutes a cry-fuss or sleep problem, we defined the presence of a problem according to parent report. However, like other researchers, we also demonstrated that infants whose parents reported problems did cry more and sleep less, on the basis of more-objective measures (the 24-hour time diaries collected at 2, 4, and 12 months).23,24 Furthermore, parent reports of sleep and cry-fuss problems are clinically relevant, are supported by the literature,25 and have shown both cross-sectional and predictive relationships with adverse outcomes in other studies.10,11
Third, the skewed nature of the parent-reported data precluded multivariate techniques such as repeated-measures multivariate analysis of variance and structural equation modeling, which would have allowed more sophisticated analyses of temporal and causal relationships. Therefore, we could not ascertain whether the data imply that cry-fuss and sleep problems cause lasting negative effects or, alternatively, are early manifestations of subsequent maternal mental health and child behavior difficulties. Clarifying causal relationships would require sampling before and/or very soon after birth to determine which problems develop first (maternal mental health and stress problems, or cry-fuss and/or sleep problems). A randomized controlled trial is unlikely to be helpful in this regard because any technique effective in reducing cry-fuss/sleep problems would probably also simultaneously target aspects of parenting and parent mental health.
These results are of interest for clinicians and for researchers. Clinicians do not need to be reminded just how common cry-fuss and sleep problems are in the first 2 years of life. This study documents clearly how distressing and stressful these problems can be for parents, even in a largely middle-class sample that can be presumed to have good access to services and reasonable family supports. In disadvantaged populations, relationships between transient sleep and cry-fuss problems and maternal stress/depression may be even stronger and/or longer lasting. However, these data can be interpreted as being good news for parents; in most cases, clinicians can confidently reassure them that the problem behaviors are likely to be transient. Efforts can be directed to providing parents with the support they need to “get through” this difficult period. In individual cases, clinicians may be able to predict which problems are likely to endure over time. They can make this clinical assessment and prediction on the basis of a number of variables that affect parent-child interactions, including parent and/or family variables that influence the perception of difficulty and the ability to cope.26
From a population perspective, however, more research is needed to find more-specific indicators that can be used in clinical settings to identify (at the most opportune time) those who will go on to have persistent rather than transient problems. This could then guide effective targeted management of the more deep-seated cry-fuss/sleep problems to avoid later adverse sequelae, with the assumption that the demonstrated relationships are indeed causal.
The PEAS Program was funded by the Community Division of the Victorian Department of Human Services, and the evaluation component was funded by the Australian Rotary Health Research Fund.
We dedicate this manuscript to our dear friend and colleague Susan Gallagher, who passed away unexpectedly during the preparation of this manuscript. We thank all of the nurses and parents who took part in the research.
- Accepted July 15, 2005.
- Address correspondence to Melissa Wake, MD, Centre for Community Child Health, Royal Children's Hospital, Flemington Rd, Parkville VIC 3052, Australia. E-mail:
The authors have indicated they have no financial relationships relevant to this article to disclose.
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- ↵Lam P, Hiscock H, Wake M. Outcomes of infant sleep problems: a longitudinal study of sleep, behavior, and maternal well-being. Pediatrics.2003;111 (3). Available at: www.pediatrics.org/cgi/content/full/111/3/e203
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- ↵Hiscock H, Wake M. Infant sleep problems and postnatal depression: a community-based study. Pediatrics.2001;107 :1317– 1322
- ↵Lehtonen L. From colic to toddlerhood. In: Barr RG, St James-Roberts I, Keefe MR, eds. New Evidence on Unexplained Early Infant Crying: Its Origins, Nature, and Management. New Brunswick, NH: Johnson & Johnson Pediatric Institute; 2001:259– 271
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- ↵Department of Human Services. Maternal and child health statewide data report 2002–2003. Available at: http://hnb.dhs.vic.gov.au/commcare/ccdnav.nsf/fid/-4902B9AE81AE6DA7CA256BEC0012C424/$file/mch_statewide_2002.pdf. Accessed March 2, 2005
- ↵Centre for Community Child Health, Royal Children's Hospital. The Parent Education and Support (PEAS) Program: Final Report Melbourne, Australia: Centre for Community Child Health, Royal Children's Hospital; 2003. Available at: http://hnb.dhs.vic.gov.au/commcare/ccdnav.nsf/fid/-057BBAE7C5BDBE67CA256F4A00161D5B/$file/mch_peas_2004.pdf. Accessed March 5, 2005
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- ↵Boyce P, Stubbs J, Todd A. The Edinburgh Postnatal Depression Scale: validation for an Australian sample. Aust NZ J Psychiatry.1993;27 :472– 476
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