Long-term Mother and Child Mental Health Effects of a Population-Based Infant Sleep Intervention: Cluster-Randomized, Controlled Trial

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ARTICLE

Long-term Mother and Child Mental Health Effects

of a Population-Based Infant Sleep Intervention:

Cluster-Randomized, Controlled Trial

Harriet Hiscock, MDa,b,c, Jordana K. Bayer, PhDa,b,c, Anne Hampton, BSa,c, Obioha C. Ukoumunne, PhDb,c,d, Melissa Wake, MDa,b,c

aCentre for Community Child Health anddClinical Epidemiology and Biostatistics Unit, Royal Children’s Hospital, Parkville, Victoria, Australia;bDepartment of Paediatrics,

University of Melbourne, Parkville, Victoria, Australia;cMurdoch Children’s Research Institute, Parkville, Victoria, Australia

The authors have indicated they have no financial relationships relevant to this article to disclose.

What’s Known on This Subject

Up to two thirds of women who report symptoms of postnatal depression also report infant sleep problems. In the short term, brief behavioral strategies can improve infant sleep problems and associated maternal depression symptoms. The long-term effect of these strategies is unknown.

What This Study Adds

Brief behavioral strategies, designed to improve infant sleep, have sustained positive effects on maternal depression symptoms at a child age of 2 years. Managing infant sleep represents a feasible, acceptable, low-intensity, and cost-effective preventive in-tervention approach for maternal depression.

ABSTRACT

OBJECTIVES.Maternal depression is an established risk for adverse child development. Two thirds of clinically significant depressive symptoms occur in mothers reporting an infant sleep problem. We aimed to determine the long-term effects of a behavioral intervention for infant sleep problems on maternal depression and parenting style, as well as on child mental health and sleep, when the children reached 2 years of age.

METHODS.We conducted a cluster-randomized trial in well-child centers across 6 government areas of Melbourne, Australia. Participants included 328 mothers re-porting an infant sleep problem at 7 months, drawn from a population sample (N

739) recruited at 4 months. We compared the usual well-child care (n⫽154) versus a brief behavior-modification program designed to improve infant sleep (n ⫽174) delivered by well-child nurses at ages 8 to 10 months and measured maternal depression symptoms (Edinburgh Postnatal Depression Scale); parenting practices (Parent Behavior Checklist); child mental health (Child Behavior Checklist); and maternal report of a sleep problem (yes or no).

RESULTS.At 2 years, mothers in the intervention group were less likely than control mothers to report clinical depression symptoms: 15.4% vs 26.4% (Edinburgh Postnatal Depression Scale community cut point) and 4.2% vs 13.2% (Edinburgh Postnatal Depression Scale clinical cut point). Neither parenting style nor child mental health differed markedly between the intervention and control groups. A total of 27.3% of children in the intervention group versus 32.6% of control children had a sleep problem.

CONCLUSIONS.The sleep intervention in infancy resulted in sustained positive effects on maternal depression symptoms and found no evidence of longer-term adverse effects on either mothers’ parenting practices or children’s mental health. This intervention demonstrated the capacity of a functioning primary care system to deliver effective, universally offered secondary prevention.Pediatrics2008;122:e621–e627

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NFANT SLEEP PROBLEMShave major implications for health care systems because they contribute substantially to long-term maternal depression, parenting stress, and child behavior problems.1The prevalence of sleep problems drops rapidly after the first year of life from ⬃45% to ⬃15% by 2 years of age, after which the prevalence remains fairly constant into the early school years.1,2 The sheer preva-lence of Australian infant sleep problems imposes a substantial population burden in the first year of life, similar to other developed countries.2,3

Maternal depression and anxiety are consistently associated with infant sleep

problems, even after controlling for known depression risk factors.4,5Postnatal depression disproportionately affects mothers whose infants suffer sleep problems, with two thirds of all mothers with Edinburgh Postnatal Depression Scale (EPDS) scores in the clinically significant range also reporting an infant sleep problem at 6 to 12 months of age.6

www.pediatrics.org/cgi/doi/10.1542/ peds.2007-3783

doi:10.1542/peds.2007-3783

Dr Hiscock had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis; Drs Hiscock and Wake were involved in the conception and design of the study and obtained funding; Drs Hiscock, and Bayer, and Ms Hampton were involved with acquisition of study data and, together with Drs Ukoumunne and Wake, were responsible for analysis and interpretation of the data; Dr Ukoumunne performed the statistical analysis with assistance from Ms Hampton; and Dr Hiscock drafted the article with critical revision from Drs Ukoumunne, Wake, Bayer, and Hampton.

This trial has been registered as Current Controlled Trials ISRCTN 48752250, registered November 2004.

Key Words

sleep, mental health, maternal depression, cluster randomized trial

Abbreviations

EPDS—Edinburgh Postnatal Depression Scale

MCH—Maternal and Child Health OR— odds ratio

CI— confidence interval

Accepted for publication May 7, 2008

Address correspondence to Harriet Hiscock, MD, Royal Children’s Hospital, Centre for Community Child Health, Flemington Road, Parkville, Victoria 3052, Australia. E-mail: harriet.hiscock@rch.org.au

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Postnatal depression short- and long-term sequelae in-clude relationship breakdown, insecure mother-child at-tachment, child cognitive, behavior and emotional prob-lems, and (in rarer cases) child abuse.7,8 Many mothers with postnatal depression are reluctant to accept this diag-nosis, medication, or therapy.9However, effectively man-aging infant sleep problems significantly reduces maternal depression symptoms, and this approach is highly accept-able to mothers6,10and cost-effective.6Thus, according to the Mrazek and Haggerty11model for mental health pro-motion, management of infant sleep problems could be viewed as a “selective” preventive intervention for some mothers with postnatal depression, whereby the interven-tion (ie, infant sleep interveninterven-tion) is “targeted to a sub-group of the population whose risk of developing mental disorders is significantly higher than average” (ie, mothers who report an infant sleep problem).

Effective management of infant sleep problems in-volves behavioral strategies, and concerns have been raised about their potential for adverse impacts in areas of infant brain development, insecure mother-child re-lationship, and later child mental health problems (eg, anxiety).12 To date no evidence exists to support such concerns, whereas substantial evidence has accumulated for the short-term benefit of behavioral sleep strategies.12 Yet, these concerns have led to community reluctance to manage infant sleep problems using behavioral strategies. In 2001, findings were published from our small ef-ficacy trial of a behavioral intervention designed to re-duce sleep problems in infants aged 6 to 12 months.4At age 3 to 4 years, we found that graduated extinction in infancy did not adversely affect later child behavior, ma-ternal depression, or family functioning.13 This study did not examine effects on the mother-child relationship. In 2004 –2005, we conducted a large effectiveness trial in which well-child nurses were trained to deliver the same brief behavioral sleep intervention to infants aged 8 months.6When infants turned both 10 and 12 months of age, mothers in the intervention group reported fewer infant sleep problems, suffered fewer depression symp-toms, and were less likely to have sought other professional help for their infant’s problem than control mothers.6

We now report on the long-term impacts of the in-tervention when the children reached the age of 2 years in this large effectiveness trial. We aimed to determine whether the positive impacts on maternal depression and child sleep were sustained to this age. On the basis of our own and others’ studies,1,3 we expected that most sleep problems would have resolved by age 2 years in both the intervention and control groups. We also aimed to determine whether there was any evidence of nega-tive impacts of the infant sleep intervention on mothers’ parenting practices or relationship quality with her child and 2-year child mental health.

METHODS

The trial was conducted in greater Melbourne, Victoria, Australia (population: 3.4 million). Melbourne has 31 local government areas, which can be ranked according to a census-based geographical index of relative disad-vantage.14 Six local government areas were selected to

provide a broad sociodemographic spread (2 in the low-est, 2 in the middle, and 2 in the highest tertile for disadvantage).

Ninety-one percent of infants born in the state of Victoria attend the free key health visit offered at 4 months of age by their assigned Maternal and Child Health (MCH) nurse.15All of the MCH nurses in the 6 local government areas participated. MCH nurses con-secutively invited mothers of 4-month-old infants at-tending in October or November 2003 to take part in the Infant Sleep Study. Infants born before 32 weeks’ ges-tation and mothers with insufficient English to complete questionnaires were excluded.

Random Assignment

When infants turned 7 months, MCH centers (clusters) were allocated to intervention or control arms using computer-generated random numbers by an indepen-dent statistician unaware of the MCH iindepen-dentifiers, thus ensuring allocation concealment. Clusters were stratified according to local government area and ranked accord-ing to size of case population; within each stratum, the largest cluster was randomly allocated and subsequent clusters alternately allocated to avoid a marked imbal-ance in cluster sizes between trial arms. Mothers who reported a sleep problem in a questionnaire adminis-tered at 7 months composed the study sample.

Intervention

Intervention nurses attended 2 structured 2.5-hour training sessions conducted by Dr Hiscock (pediatrician) and Dr Bayer (child psychologist), supported by a written manual. Training incorporated didactic teaching, written information, role-play sessions, and trouble-shooting common problems (such as partner conflict over sleep management). Nurses were trained regarding how to instruct families in the use of the 2 widely practiced behavioral interventions, namely graduated extinction (“controlled crying”) and adult fading (“camping out”).16–18 Two different structured behavioral interven-tions were taught, because Dr Hiscock’s clinical experi-ence suggested that different families prefer different sleep management approaches. In graduated extinction, parents respond to their infant’s cry at increasing time intervals (ie, 2, 4, 6, 8, to 10 minutes), allowing an infant to learn to fall asleep by him or herself. Adult fading is an even more graduated approach to managing infant sleep problems, in which a parent sits with their infant until they fall asleep and slowly removes their parental pres-ence over 2 to 3 weeks.

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role in sleep problems. Handouts on managing problem overnight feeding (ie, reducing volume or time spent feeding over a week) and pacifiers (ie, removal or teach-ing infant to replace his or her own pacifier) were also tailored into the individualized sleep plan as needed.

Measures

Mothers completed a written questionnaire when their child turned 10 months, 12 months, and 2 years old (ie, 17 months after random assignment). The primary out-come of maternal depression was measured by the EPDS (cut point for depression in the community is a score of

⬎9 and in clinical samples is⬎12).19,20Mothers’ parent-ing practices were measured with the Parent Behavior Checklist, which yields standardized t scores for both harsh discipline and nurturing (with mean of 50 and SD of 10).21Child mental health was assessed with the Child Behavior Checklist for children aged 18 months to 5 years, which yields standardized t scores for externalizing and internalizing behavior problems.22 Mothers also reported the presence of current child sleep problems (“Over the last 2 weeks, has your child’s sleep generally been a problem for you?” yes or no). In 2 large community studies, mater-nal report of an infant sleep problem is a strong predictor of frequent and prolonged night wakings and difficulty set-tling to sleep.4,23 Potential confounders measured were mothers’ rating of temperament on the single-item 5-point Global Infant Temperament Scale24and overall confidence in the competence of their nurse’s health advice on a 4-point ordinal study-designed scale.

Mothers in the intervention group reported on the quality of their relationship with their child as a result of the earlier sleep intervention. Mothers were asked, “Think about the strategies your MCH nurse recommended (eg, leaving your child to settle to sleep by themselves even if it involved short periods of your child crying). Do you think these strategies have changed your relationship with your child at all?” Mothers responded on a study-designed 10-point visual analog scale ranging from 0, “relationship worse,” to 10, “relationship better.”

The project was approved by the ethics in human research committee of Melbourne’s Royal Children’s Hospital (EHRC23067C). The trial was conducted in ac-cordance with the Consolidated Standards of Reporting Trials statement for cluster-randomized trials,25and all of the mothers gave written, informed consent.

Sample Size

Sleep was the primary short-term outcome of the trial, and, therefore, the sample size was based on detecting a difference of 20% between the proportions of mothers reporting infant sleep problems at each of the 10- and 12-month follow-ups (reported by 70% of the control group and 50% of the intervention group in our previ-ous efficacy trial).10 An individually randomized trial would require 103 infants in each arm to have 80% power at the 5% level of significance. This sample size was inflated by a design effect of 1.2 to 124 infants per trial arm to allow for correlation between responses within the same cluster (ie, MCH center),26 with an

expected average cluster size of 11 (ie, number of eligible mothers attending the center) and intracluster correla-tion coefficient of 0.02.

Analyses

The trial groups were analyzed as randomized, applying the intention-to-treat principle.25Because of the nature of the intervention, it was not possible to blind either the nurses or the mothers. Allocation concealment at ran-dom assignment and blinding of the data entry process took place. Outcomes were compared between the intervention and control groups, adjusting for poten-tial confounders selected a priori on the basis of our previous research6,10(see Table 3 footnote). To allow for clustering, quantitative outcomes were analyzed us-ing random-effects linear regression fitted usus-ing full in-formation maximum likelihood estimation,27 and di-chotomous outcomes were analyzed using marginal logistic regression models fitted using generalized esti-mating equations with information sandwich estimates of SEs.28An exchangeable correlation matrix was spec-ified for the generalized estimating equation analyses. Ordinary logistic regression was used to analyze the sleep problem outcome, because this had a negative intracluster correlation coefficient. Confidence intervals from analyses of quantitative outcomes were validated using the bootstrap method.29Analyses were conducted by using Stata 9.2 (Stata Corp, College Station, TX).

RESULTS

At 4 months, 739 infants were recruited and mothers of 695 infants (94%) completed the 7-month question-naire. Of these, 328 mothers reported an infant sleep problem and participated in the intervention trial. In accordance with how their MCH center was random-ized, 174 were allocated to the intervention group and 154 mothers to the control group (see Fig 1). In this “real-world” effectiveness trial, 100 of 174 intervention families took up the offer of help from their nurse. Of these 100 families, 53 families chose graduated extinc-tion, 7 families chose adult fading, and for 40 families, nurses indicated simple strategies, such as the develop-ment of a positive bedtime routine or managedevelop-ment of pacifiers overnight (n⫽20), or nurses did not note their choice of behavioral technique (n⫽20).

Characteristics of the participants at baseline are pre-sented in Table 1, showing that the 2 arms were bal-anced. Mothers in the intervention group attended their nurse specifically for sleep advice for an average of 1.52 visits (recorded by nurses); their first visit lasted on average 25 minutes, and follow-up visits lasted on aver-age 19 minutes. In the control arm, 34 of 154 mothers also reported receiving some help from their nurse for their infant’s sleep problem (none of these nurses had received the structured training but still provided care to families, as per usual care), and these mothers averaged 1.32 visits per family.

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con-founding variables and loss to follow-up in the interven-tion arm; but in the control arm, mothers of female children and those from a disadvantaged background and/or with lower levels of education were dispropor-tionately more likely to be lost to follow-up (Table 2). However, none of these demographics was strongly as-sociated with the baseline EPDS dichotomous measures (allPvalues were⬎.3), so we did not adjust for them in the regression analyses.

Table 3 shows the main outcome comparisons at 2 years of age. Mothers in the intervention group were significantly less likely to report clinical levels of depres-sion symptoms than control mothers (EPDS⬎9: 15.4% vs 26.4%; adjusted odds ratio [OR]: 0.41 [95% confi-dence interval (CI): 0.20 to 0.86]; P ⫽ .02), and the mean depression scores were also lower for intervention compared with control mothers (EPDS score: 5.50 vs 6.72; adjusted mean difference: ⫺1.47 [95% CI:⫺2.42 to ⫺0.51]; P ⫽ .003). Even when applying the more

stringent clinical cut point of EPDS ofⱖ13, mothers in the intervention group remained substantially less likely to report clinical levels of depression symptoms than control mothers (4.2% vs 13.2%; adjusted OR: 0.20 [95% CI: 0.07 to 0.60]; P ⫽ .004). Neither parenting practices (harsh discipline and nurturing) nor child men-tal health (externalizing and internalizing behavior problems) differed markedly between the intervention and control groups. Both intervention and control group T distributions for parenting and child mental health were comparable to community standardized norms (mean: 50 [SD: 10]).21,22

At 2 years, 27.3% (39 of 143) of mothers in the intervention group reported child sleep problems com-pared with 32.6% (42 of 129) of control mothers (ad-justed OR: 0.83 [95% CI: 0.48 to 1.43]; P ⫽ .49). A smaller proportion of intervention rather than control mothers reported sleep problems that persisted through-out the entire study, that is, at all 3 of the 10-, 12-, and

7-mo questionnaire returned n = 695 families

Excluded n = 367 families (no sleep problem)

Randomly assigned n = 328 families, n = 49 MCH centre clusters

Allocated to control n = 154 families

n = 24 MCH center clusters

Median cluster size 6 families, range 2–15

Analyzed n = 168 families

n = 25 MCH clusters

Median cluster size 7 families, range 2–20

Excluded from analysis n = 6 families

n = 0 MCH clusters

Analyzed n = 151 families

n = 24 MCH clusters

Median cluster size 6 families, range 2–15

Excluded from analysis n = 3 families

n = 0 MCH clusters

Enr

o

llme

nt

Allocation

12-mo analysis

Allocated to intervention n = 174 families

n = 25 MCH center clusters

Median cluster size 7 families, range 2–21

Received allocated intervention n = 100 families (25 clusters)a Did not receive allocated intervention n = 74 families

Analyzed n = 143 families

n = 25 MCH clusters

Median cluster size 6 families, range 1–17

Excluded from analysis n = 31 families

n = 0 MCH clusters

2-y

Analysis

Analyzed n = 129 families

n = 24 MCH clusters

Median cluster size 4.5 families, range 1–14

Excluded from analysis n = 25 families

n = 0 MCH clusters

Follow-up

(2 y)

Lost to follow-up (2 y)b n = 31 families

Lost to follow-up (2 y)b n = 25 families

FIGURE 1

Flowchart of participants.aTake-up of the intervention

was voluntary. One hundred families reported receiving the intervention;ball lost to follow-up because of failure to

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24-month assessment times (11.2% [16 of 142] vs 21.7% [28 of 129]; adjusted OR: 0.51 [95% CI: 0.25 to 1.03];P⫽.06).

Fifty-five mothers in the intervention group reported on how the infant sleep management strategies had affected the relationship quality with their child. Moth-ers strongly endorsed both behavioral interventions, with 84% (46 of 55) rating these as having had a positive effect on their relationship with their child. On the 10-point scale (on which 0⫽very negative effect and 10⫽ very positive effect on relationship), the median score was 6.2 (interquartile range: 5.0 – 8.3), and the lowest rating was 4.8.

DISCUSSION

This is the first effectiveness randomized trial to report on long-term effects of behavioral interventions for in-fant sleep problems, delivered systematically at the pop-ulation level. Sixteen months after delivery (when the child was 2 years old), the intervention still had a ben-eficial impact in reducing maternal depression symp-toms, with the odds of reporting depression symptoms 59% lower for intervention relative to control group mothers. This was achieved although only 57% of moth-ers in the intervention group had chosen to take up the sleep intervention in infancy.

The intervention did not have a long-term impact (positive or negative) on parenting practices or child

mental health. The majority of mothers in the interven-tion group reported that the sleep interveninterven-tion in in-fancy had a positive effect on their relationship with their child. Sleep problems had largely resolved in both groups by 2 years, which is consistent with previous literature.1,3Furthermore, only half as many mothers in the intervention group as control mothers reported sleep problems at all of the follow-up points (10, 12, and 24 months). Reduction in the prevalence of persistent sleep problems could at least partly explain the lasting reduc-tion in maternal depression symptoms, because we have shown previously that it is persistent, rather than tran-sient, sleep problems that predict poorer maternal men-tal health by the time the child is aged 2 years.1It may also be possible that improved maternal mood and sleep in late infancy led to improvement in maternal parent-ing abilities and subsequently more positive mother-child interactions. In turn, this could have lead to lasting improvements in maternal confidence and mood at child age 2 years. The effectiveness trial was conducted in a “real world” setting, conformed to the rigorous standards of the Consolidated Standards of Reporting Trials state-ment, and used validated outcome measures for mater-nal depression, parenting practices, and child mental health. All of the clusters and 83% of families were followed up. Families who completed the follow-up did not differ from those that did not in terms of maternal depression scores or infant sleep severity. Thus, results are likely to generalize to English-speaking families and mothers with varying degrees of depression symptoms.

The study had some limitations. First, all of the out-comes were parent report measures, which may have biased results in the intervention group toward more favorable responses, because they could not be blinded. In our previous short-term follow-up at 12 months, however, mothers in the intervention group reported poorer physical health than control mothers, suggesting that response bias of mothers in the intervention group is unlikely.6Second, sleep problem status and mother-child relationship were measured by maternal percep-tion of a problem. Maternal report of a sleep problem, however, is a reliable indicator of sleep patterns in in-fants, as validated against overnight infrared video re-cording, actigraphy, and more detailed maternal ratings of shorter sleep hours, more frequent and prolonged night wakings, and longer settling times.4,18,23 A third study limitation was that very few mothers reported extreme depression scores, so findings cannot be gener-alized to mothers with severe depression or postpartum psychosis. Also, formal child attachment classification was not used in this large effectiveness trial, because its intensive direct observation protocol virtually rules out its use in population studies such as this. Finally, because not all of the mothers in the intervention group received the trial intervention, it might be surmised that simply talking to their nurse led to improvement in maternal mood. However, we did not offer, or have time to offer, any additional training or counseling in active listening strategies, which have sometimes been shown to be effective for postnatal depression.30 In addition, the mother’s visits were short and highly structured and as TABLE 1 Baseline Characteristics According to Trial Arm

Variable Intervention

(N⫽174)

Control (N⫽154)

Infant characteristic

Female child,n(%) 85 (48.9) 65 (42.2) Child’s age, mean (SD), mo 7.4 (0.6) 7.3 (0.6) Child has difficult temperament,n(%) 40 (23.0) 44 (28.6) Family characteristic

Maternal age, mean (SD), y 32.8 (4.3) 33.2 (4.8) Has partner,n(%) 172 (98.9) 145 (96.7) Mother born in Australia or New

Zealand,n(%)

139 (79.9) 124 (80.5)

Father born in Australia or New Zealand,n(%)

137 (79.2) 124 (82.1)

Speaks language other than English at home,n(%)

32 (18.4) 31 (20.3)

Mother’s education level,n(%)

Did not complete high school 29 (16.7) 28 (18.2) Completed high school 53 (30.5) 51 (33.1) Completed tertiary/postgraduate 92 (52.9) 75 (48.7) Father’s education level,n(%)

Did not complete high school 49 (28.7) 43 (28.1) Completed high school 45 (26.3) 44 (28.8) Completed tertiary/postgraduate 77 (45.0) 66 (43.1) Index of social disadvantage,n(%)

High disadvantage 24 (13.8) 35 (22.7) Medium disadvantage 63 (36.2) 41 (26.6) Low disadvantage 87 (50.0) 78 (50.6) Maternal health

EPDS score, mean (SD) 8.4 (5.3) 8.4 (5.1) EPDS score⬎9,n(%) 66 (37.9) 64 (41.6) Ever diagnosed with depression,n(%) 36 (20.7) 32 (20.8)

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such there was little time for the nurse to engage in any discussions other than those around infant sleep.

The long-term effects of this infant sleep intervention on maternal depression seem to outstrip those of other interventions, including those focusing specifically on maternal mood. Sixty-eight percent of high depression scores in the baseline survey at 7 months occurred in mothers who also report an infant sleep problem.6 Mothers who report an infant sleep problem, therefore, represent a readily identifiable “at-risk” subgroup for depression. Managing infant sleep represents a feasible, acceptable, low-intensity, and cost-effective preventive intervention approach for maternal depression.10 Be-cause this approach has the potential to reach two thirds of the population experiencing depressive symptoms, it represents a major public health gain. In a systematic review of psychosocial and psychological interventions for preventing postnatal depression in the first year post-partum (when our intervention was delivered), the au-thors concluded that psychosocial intervention was as

effective as standard care.31 Only 1 small randomized, controlled trial has examined the effects of antidepres-sant medication on postnatal depression and found that fluoxetine was as effective as cognitive behavioral ther-apy in reducing depression.32The American Academy of Pediatrics has indicated concern about the use of anti-depressant medications in breastfeeding mothers be-cause of unknown effects on the developing child. Many breastfeeding mothers themselves report reluctance to take antidepressant medication.30Thus, our effective ap-proach to reducing postnatal depression involving infant sleep management may prove more acceptable to moth-ers in the first instance, because it does not stipulate antidepressant medication.

CONCLUSIONS

A brief behavioral intervention for infant sleep problems in the second 6 months of life delivered at a population level had a lasting impact on reducing maternal depres-sion symptoms at 2 years. This demonstrates the capacity TABLE 2 Selected Baseline Characteristics (Prognostic Variables) According to Follow-up Status at

2 Years

Variables Participants Lost to Follow-up Remaining Participants

Intervention (N⫽31)

Control (N⫽25)

Intervention (N⫽143)

Control (N⫽129)

Female child,n(%) 17 (54.8) 16 (64.0) 68 (47.6) 49 (38.0) Child has difficult temperament,n(%) 8 (25.8) 7 (28.0) 32 (22.4) 37 (28.7) Index of social disadvantage,n(%)

High disadvantage 5 (16.1) 9 (36.0) 19 (13.3) 26 (20.2)

Medium disadvantage 11 (35.5) 5 (20.0) 52 (36.4) 36 (27.9)

Low disadvantage 15 (48.4) 11 (44.0) 72 (50.3) 67 (51.9)

Mother’s education level,n(%)

Did not complete high school 5 (16.3) 7 (28.0) 24 (16.8) 21 (16.3) Completed high school 7 (22.6) 8 (32.0) 46 (32.2) 43 (33.3) Completed tertiary/postgraduate 19 (61.3) 10 (40) 73 (51.0) 65 (50.4) EPDS score, mean (SD) 7.7 (5.8) 8.7 (4.3) 8.5 (5.1) 8.3 (5.3) EPDS score⬎9,n(%) 10 (32.3) 11 (44.0) 56 (39.2) 53 (41.1)

TABLE 3 Main Outcome Comparisons at 2 Years

Outcome Intervention Arm Control Arm Unadjusted

Mean Differencea

Adjusted Mean Differenceb,c

Estimate n Estimate n Estimate 95% CI P ICCd

EPDS score, mean (SD) 5.50 (4.23) 143 6.72 (5.17) 129 ⫺1.22 ⫺1.47 ⫺2.42 to⫺0.51 .003 0 EPDS score⬎9,n(%) 22 (15.4) 143 34 (26.4) 129 0.50 0.41 0.20 to 0.86 .02 0.009 Harsh parenting, mean (SD) 42.5 (8.4) 143 42.0 (9.2) 128 0.31 0.16 ⫺2.21 to 2.53 .89 0.038 Nurturing parenting, mean (SD) 52.7 (9.4) 143 54.7 (11.4) 128 ⫺1.89 ⫺1.64 ⫺4.33 to 1.07 .24 0.014 Internalizing problems, mean (SD) 46.5 (9.2) 142 46.3 (10.0) 126 0.24 0.50 ⫺1.78 to 2.77 .67 0 Externalizing problems, mean (SD) 49.8 (9.1) 142 49.2 (9.3) 126 0.61 0.37 ⫺2.05 to 2.80 .76 0.035 Child sleep problem,n(%) 39 (27.3) 143 42 (32.6) 129 0.78 0.83 0.48 to 1.43 .49 0

aORs are shown for sleep problem and EPDS score of9 outcomes. Ordinary logistic regression was used for sleep problem outcome and marginal logistic regression fitted using generalized

estimating equations used for EPDS score of⬎9. Random-effects linear regression fitted using full information maximum likelihood estimation was used for all of the outcomes. Data show the intervention arm minus the control arm.

bSample sizes in adjusted analyses ranged from 127 to 143 in the intervention arm and from 119 to 129 in the control arm. The number of intervention arm clusters involved in the adjusted analysis

dropped from 25 to 24 for all of the outcomes other than sleep problem and EPDS score of⬎9. Data show the intervention arm minus the control arm.

cAnalysis of sleep problem was adjusted for Socio-Economic Index for Areas disadvantage index score, maternal education, and parent-rated nurse competency. Analysis of EPDS scores of9 was

adjusted for EPDS total score at baseline. (Analysis was not fully adjusted for factors below, because there were potentially too few subjects with EPDS⬎9 to obtain stable estimates from regression models that included all of the potential confounders as predictors. The omitted factors were not strongly related to the EPDS score of⬎9 outcome, that is, all of thePvalues were⬎.3.) Analyses of all of the other outcomes were adjusted for Socio-Economic Index for Areas disadvantage index score, maternal education and nurse competency, child gender, global infant temperament score, and EPDS total score at baseline.

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of a functioning well-child system to deliver effective, universally offered secondary prevention to reduce an important problem affecting a large proportion of the population. This approach could equally be delivered through other systematic primary care models, such as pediatric practices. Managing infant sleep problems should not be the primary clinical approach to postnatal depression, but at a population level it may be a very important component.

ACKNOWLEDGMENTS

This project was funded by the Pratt Foundation. The salaries of Drs Hiscock and Ukoumunne are funded by the National Health and Medical Research Council Ca-pacity Building Grant. Dr Bayer’s salary is funded by the Colin Dodds Postdoctoral Fellowship from the Australian Rotary Health Research Fund.

We thank the Maternal and Child Health nurses and families of the cities of Bayside, Darebin, Hobson’s Bay, Manningham, and Monash and the Shire of Yarra Ranges who took part in this study.

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DOI: 10.1542/peds.2007-3783

2008;122;e621

Pediatrics

Melissa Wake

Harriet Hiscock, Jordana K. Bayer, Anne Hampton, Obioha C. Ukoumunne and

Infant Sleep Intervention: Cluster-Randomized, Controlled Trial

Long-term Mother and Child Mental Health Effects of a Population-Based

Services

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(9)

DOI: 10.1542/peds.2007-3783

2008;122;e621

Pediatrics

Melissa Wake

Harriet Hiscock, Jordana K. Bayer, Anne Hampton, Obioha C. Ukoumunne and

Infant Sleep Intervention: Cluster-Randomized, Controlled Trial

Long-term Mother and Child Mental Health Effects of a Population-Based

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Figure

Table 3 shows the main outcome comparisons at 2

Table 3

shows the main outcome comparisons at 2 p.4
TABLE 1Baseline Characteristics According to Trial Arm

TABLE 1Baseline

Characteristics According to Trial Arm p.5
TABLE 2Selected Baseline Characteristics (Prognostic Variables) According to Follow-up Status at2 Years

TABLE 2Selected

Baseline Characteristics (Prognostic Variables) According to Follow-up Status at2 Years p.6
TABLE 3Main Outcome Comparisons at 2 Years

TABLE 3Main

Outcome Comparisons at 2 Years p.6

References