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Compared With Cot Sleeping In The Home Setting Differences In Infant And Parent Behaviors During Routine Bed Sharing
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Compared With Cot Sleeping In The Home Setting Differences In Infant And Parent Behaviors During Routine Bed Sharing


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  • 1. Differences in Infant and Parent Behaviors During Routine Bed Sharing Compared With Cot Sleeping in the Home Setting Sally A. Baddock, Barbara C. Galland, David P.G. Bolton, Sheila M. Williams and Barry J. Taylor Pediatrics 2006;117;1599-1607 DOI: 10.1542/peds.2005-1636 The online version of this article, along with updated information and services, is located on the World Wide Web at: PEDIATRICS is the official journal of the American Academy of Pediatrics. A monthly publication, it has been published continuously since 1948. PEDIATRICS is owned, published, and trademarked by the American Academy of Pediatrics, 141 Northwest Point Boulevard, Elk Grove Village, Illinois, 60007. Copyright © 2006 by the American Academy of Pediatrics. All rights reserved. Print ISSN: 0031-4005. Online ISSN: 1098-4275. Downloaded from by on September 6, 2009
  • 2. ARTICLE Differences in Infant and Parent Behaviors During Routine Bed Sharing Compared With Cot Sleeping in the Home Setting Sally A. Baddock, PhDa, Barbara C. Galland, PhDa, David P. G. Bolton, MRCP, PhDb, Sheila M. Williams, DScc, Barry J. Taylor, MBChB, FRACPa a Departments of Women’s and Children’s Health and cPreventive and Social Medicine, Dunedin School of Medicine, and bDepartment of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand The authors have indicated they have no financial relationships relevant to this article to disclose. ABSTRACT OBJECTIVES. To observe the behavior of infants sleeping in the natural physical environment of home, comparing the 2 different sleep practices of bed sharing and cot sleeping quantifying to factors that have been identified as potential risks or peds.2005-1636 benefits. doi:10.1542/peds.2005-1636 METHODS. Forty routine bed-sharing infants, aged 5–27 weeks were matched for age Key Words cosleeping, SIDS, breastfeeding, sleep and season of study with 40 routine cot-sleeping infants. Overnight video and Abbreviation physiologic data of bed-share infants and cot-sleep infants were recorded in the SIDS—sudden infant death syndrome infants’ own homes. Sleep time, sleep position, movements, feeding, blanket Accepted for publication Oct 17, 2005 height, parental checks, and time out of the bed or cot were logged. Address correspondence to Barry Taylor, MBChB, FRACP, Department of Women’s and RESULTS. The total sleep time was similar in both groups (bed-sharing median: 8.6 Children’s Health, University of Otago, PO Box 913, Dunedin, New Zealand. E-mail: barry. hours; cot-sleeping median: 8.2 hours). Bed-sharing infants spent most time in the side position (median: 5.7 hours, 66% of sleep time) and most commonly woke at PEDIATRICS (ISSN Numbers: Print, 0031-4005; the end of sleep in this position, whereas cot-sleeping infants most commonly slept Online, 1098-4275). Copyright © 2006 by the American Academy of Pediatrics supine (median: 7.5 hours, 100%) and woke at the end of sleep in the supine position. Prone sleep was uncommon in both groups. Head covering above the eyes occurred in 22 bed-sharing infants and 1 cot-sleeping infant. Five of these bed-sharing infants were head covered at final waking time, but the cot-sleeping infant was not. Bed-sharing parents looked at or touched their infant more often (median: 11 vs 4 times per night) but did not always fully wake to do so. Movement episodes were shorter in the bed-sharing group as was total movement time (37 vs 50 minutes respectively), whereas feeding was 3.7 times more frequent in the bed-sharing group than the cot-sleeping group. CONCLUSIONS. Bed-share infants without known risk factors for sudden infant death syndrome (SIDS) experience increased maternal touching and looking, increased breastfeeding, and faster and more frequent maternal responses. This high level of interaction is unlikely to occur if maternal arousal is impaired, for example, by alcohol or overtiredness. Increased head covering and side sleep position occur during bed-sharing, but whether these factors increase the risk of SIDS, as they do in cot sleeping, requires further investigation. PEDIATRICS Volume 117, Number 5, May 2006 1599 Downloaded from by on September 6, 2009
  • 3. M ANY GROUPS VALUE bed sharing, whether as a traditional practice, a positive parenting choice, or a way of coping with the demands of an infant.1–3 home environment, comparing the 2 different sleep practices of bed sharing and cot sleeping. This was to identify the differences between groups in regard to These varied motivations lead to considerable heteroge- sleep time, sleep position, movements, feeding, blanket neity with regard to the actual practices involved.2,4–6 The height, and parental checks, which may contribute to practice is relatively common in the United Kingdom7 the mechanisms underlying risks and benefits identified and has become more common in Western countries in from epidemiologic data. the last 10 years, for example, the United States,8 Nor- way,9 and the Netherlands.10 This is in part coincident METHODS with the promotion of breastfeeding.9 Many advantages Two groups of infants were studied: 40 bed-sharing in- have been documented, for example, increased breast- fants and 40 cot-sleeping infants. The sleep practice cri- feeding,11,12 increased mother-infant interactions,12 and teria was that bed-sharing infants regularly slept in the increased infant arousals.12 However, bed sharing has parental bed for a minimum of 5 hours per night also been identified as a risk factor for sudden infant whereas cot-sleeping infants regularly slept in a cot or death syndrome (SIDS) in combination with maternal bassinette in the parental bedroom 5 hours per night. smoking,13–15 alcohol consumption,14,15 maternal over- None of the infants reported prenatal or postnatal com- tiredness,14 excessive or soft bedding,16 bed sharing with plications (questionnaire). Bed-sharing infants were re- someone other than parents,17 and younger infant cruited through local postnatal groups and media adver- age.14,15,18 There may also be separate risks associated tising. Cot-sleeping infants matched for age and season with sleeping in an adult bed without adults, similar to of study were recruited from the local maternity ward. those identified with sleeping in any unusual place.14 Infants were aged 0 – 6 months with 13 infant pairs aged The recent policy statement of the American Academy of 0 –12.9 weeks, 15 pairs aged 13–19.9 weeks, and 12 pairs Pediatrics did not target these risk factors but recom- aged 20 –27 weeks. All of the infants were at 37 weeks’ mended against bed sharing during sleep.19 There are a gestation (except 2 infants in each group who were 28 number of postulated mechanisms for this increased risk and 32 weeks’ gestation). The age of the 4 premature but little research to provide evidence for them in the infants was adjusted to be consistent with 40 weeks’ bed-share situation. gestation. There were 14 pairs of studies in the winter There is a need to identify benefits and risks to the compared with 8 to 10 studies in each of the other infant and parent(s) to understand the ways bed sharing seasons. The study was approved by the Southern Re- could be made safer for all infants. The change away gional Health Authority Ethics Committee, New Zealand from the prone sleep position has been very successful in (protocol 97/04/036). Informed consent was obtained many cultures at reducing the SIDS rate,20 but changes from the parent(s) of all of the infants studied. to other potentially modifiable factors have met with limited success.15,21 It may be more realistic and of more Protocol benefit to families that value bed sharing to identify Infants were monitored over 2 consecutive nights in ways to make it safer rather than increase guilt about their own home. The first night involved video recording what is a common and, for many cultures, a valued only, and the second involved video and physiologic child-care practice. recording. The physiologic recordings involved place- When trying to assess the risks or benefits of bed ment of electrodes for recording raw electrocardiogram, sharing, cot sleeping is often taken as the norm; how- oxygen saturation and heart rate, abdominal and chest ever, within many cultures, bed sharing is the norm or movements of respiratory pattern, nasal airflow, shin has historically been so.22 It is important to identify and rectal temperature, and CO2 near the infant’s face. normative data for bed sharing rather than treating the 2 The details of these recordings have been described pre- environments as if they are the same. Three groups have viously.25 Infants were set up and recordings started by published findings from observational studies of infants the researchers. Families were then left unattended for sleeping overnight in a bed-share situation.12,23,24 These the night. Recordings were turned off in the morning studies have been in sleep laboratories with infants at when the researchers returned. For the behavioral re- low risk of SIDS using a crossover design so that infants cordings, a small surveillance camera (CEC-C38, Pana- act as their own controls. This, however, means that sonic, Osaka, Japan) was mounted on a stand above the infants are asked to sleep nights in a situation that is not bed so that the full width and the top third of the bed their usual practice. As far as we are aware, there are no were in the field of view to allow recordings of the published studies of overnight family behavior con- infant’s movements and positioning and any infant/par- ducted in the home environment comparing bed sharing ent interactions. A small, handheld portable television and infant cot sleep. was used as a monitor to ensure correct positioning. An The aim of this study, therefore, was to observe and infrared light source (Dennard [Fleet, United Kingdom] document the behavior of families sleeping in their 12 volt. 880 Med 50) was mounted on the stand to 1600 BADDOCK et al Downloaded from by on September 6, 2009
  • 4. reflect light off the ceiling on to the recording area. The the 5% level of significance, have 80% power to show camera was connected to an analog video recorder this difference between groups. (Panasonic AG-TL700) set to “long play” that allowed 15 Although bed-share and cot-sleep infants were hours of recording on a 3-hour videotape. matched for age and season of study, data for both members of 4 pairs were not available. Data were, there- fore, analyzed as 2 groups, and regression analysis, ad- Video Analysis justing for infant age and season, was used to take the Analysis of the video data for sleep time, sleep position, matching into account. Medians and interquartile ranges movements, feeding, blanket height, and parental are presented to describe the data. A Kruskal-Wallis test, checks was based on observations on the second night, Poisson or negative binomial regression, to account for allowing synchronization with physiologic recordings. the overdispersion in the data, or linear regression based Custom-developed computer software was used to log on log transformation values were used to compare the all of the significant events into a database with time 2 groups for the behavior variables. Results, where ap- code for correlation with the physiologic readings. C propriate, are presented as the risk ratios and 95% con- Video software (Envisionology, San Francisco, CA) and a fidence intervals. connecting cable were used to link the time counter from the video player with a key command on the RESULTS computer. The database (File Maker Pro 2.0; Claris Cor- As shown in Table 1, bed-sharing and cot-sleeping in- poration, Santa Clara, CA) was customized to provide a fants were comparable with regard to gestational age, file for each major behavior category and subcategory. birth weight, male:female ratio, age at study, and weight The start and finish times and code for each event were at study. All of the bed-sharing infants and 35 of 40 logged in the database using computer key commands. cot-sleeping infants were breastfed. The age of the The video counter was calibrated with the real time mother and the proportion of mothers educated to ter- digitized on the recording tape. Although tapes were tiary level were similar between the groups. A small recorded as long play, they were viewed at normal tape number in both groups were identified as Maori, indig- speed. enous New Zealanders. Maternal smoking was more Off-line logging of data started from when the infant common in the cot group (25%) compared with the was asleep. Sleep was identified from the video and bed-sharing group (8%). Maternal alcohol consumption defined as starting after the infant was settled for 2 was minimal in all, ranging from “rarely” to 3 glasses of minutes. Start and stop times for behavioral categories wine or beer per week, with 17 of 40 bed sharers and 15 listed here were logged into the database from this start of 40 mothers of cot sleepers reporting no alcohol con- time until the final waking of the infant in the morning. sumption during or after pregnancy. The practice of bed Subcategories for sleep position were: side, prone, and sharing was reported to be adopted by mothers because supine; for blanket height: below chin, chin to eyes, and of factors such as the ease of breastfeeding, the provision above eyes; for parental checks: father look, father of a close and secure environment for the infant, a more touch, mother look, and mother touch; for infant move- settled infant, and a natural environment. ments: small movement, posture change (trunk or gross body movement), response to parent (any infant move- Total Sleep Time and Sleep Efficiency ment that occurred after movement by the adjacent The total study time was similar between groups (bed adult), feeding, and time out of the cot. Sleep and awake sharing: median, 9.7 hours [interquartile range: 8.8 – periods were identified from the video. If the infant 10.2 hours]; cot-sleeping: median, 9.0 [interquartile awoke during sleep and returned to a settled state within range: 8.7–10.2]). The total sleep time, as determined by 2 minutes, this period was included as sleep. Awaken- video observation, was also similar (bed sharing: me- ings that lasted for 2 minutes were described as awake. dian, 8.6 hours [interquartile range: 7.8 –9.4]; cot-sleep- Study time was defined from when the infant was first ing: median, 8.2 [interquartile range: 7.4 –9.0]). Conse- asleep, regardless of the presence of an adult, until the quently, sleep efficiency was similar between groups infant woke in the morning. Sleep time was the accu- (bed sharing: median, 90.7% [interquartile range: 87.1– mulation of the infant sleep periods during the study 94.6]; cot-sleeping: median, 87.1 [interquartile range: time. Sleep efficiency was expressed as the percentage of 84.1–96.2]). total sleep time/total study time. Infant Sleep Position Statistical Analyses The time spent in each of the 3 sleep positions (as Based on studies of high-risk behavior in cot-sleeping defined by the infant trunk position) varied between the infants,26 it was predicted that 50% of bed-sharing and 2 groups of infants and is shown in Table 2. Bed-sharing 20% of cot-sleeping infants were likely to experience a infants spent most time in the side position (median: 5.7 potentially dangerous event. Two samples of 40, using hours, 66% sleep time) whereas cot-sleeping infants PEDIATRICS Volume 117, Number 5, May 2006 1601 Downloaded from by on September 6, 2009
  • 5. TABLE 1 Infant and Maternal Group Characteristics Study Group Bed Sharing Cot Sleeping P (n 40) (n 40) Infant characteristics Study age, wka 15.3 (9.9–20.4) 16.5 (10.0–21.0) .93 Birth weight, ga 3615 (3190–4100) 3595 (3310–3965) .86 Gestation, wka 40.5 (39.0–41.0) 40 (39.0–41.0)b .62 Study weight, ga 6450 (5605–7755) 6720 (5700–7590)b .84 Sex (female)c 17 (43) 18 (45) .90 Breastfedd 40 (100) 35 (88) .05 Maternal characteristics (n) Smoking at mid-trimesterd (38) 3 (8) 10 (25) .06 Tertiary educationde (26) 23 (88) 25 (96) .31 Ethnicityc (40) Maori 4 (10) 7 (18) European 31 (78) 23 (58) .18 Other 5 (13) 10 (25) Data are median (interquartile range) or n (%). a Kruskal-Wallis test. b Data missing from 1 infant. c 2 test. d Fisher’s exact test. e Tertiary refers to any post– high school education. TABLE 2 Infant Sleep Position: Duration and Percentage of Sleep Time in Each Position Infant Sleep Position Bed Sharing, Median Cot Sleeping, Median Bed Sharing/Cot Sleeping, P (interquartile range) (interquartile range) Risk Ratio (95% CI) Side h/study 5.74 (3.18–7.90) 0 (0–2.02) 4.71 (1.72–12.86) .003 % sleep timea 66 (37–93) 0 (0–25) .0001 Supine h/study 2.10 (0.45–5.95) 7.45 (4.92–9.33) 0.42 (0.23–0.76) .004 % sleep timea 22 (7–63) 100 (56–100) .0001 Prone h/study 0.08 (0.04–0.20) 0 (0–0) 5.44 (0.16–1811) .57 % sleep timea 0 (0–0) 0 (0–0) .17 Adjusted for age, season of study, and total sleep time. CI indicates confidence interval. a Tests were negative binomial regression except those marked for Kruskal Wallis. most commonly slept supine (median: 7.5 hours, 100% fants spent significantly more time than cot infants with sleep time). The median time spent prone was not sig- the blankets partially over the face (to the eyes) or with nificantly different. At the end of the final sleep period, blankets above the eyes. Head-covering events (ie, blan- a similar distribution of sleep positions was observed. kets above the eyes) occurred in 22 bed-sharing infants Bed-sharing infants were most commonly on their side and 1 cot-sleeping infant. At final awakening time, 5 of (side: 23 infants; supine: 13; prone: 2), whereas cot- these bed-share infants had their head covered. The last sleeping infants were commonly supine (side: 4 infants; head-covering incident for the cot-sleep infant finished 4 supine: 33; prone: 2). The pattern of prone sleep varied hours before final waking. between the 2 groups: 5 bed-sharing infants (aged 7, 8, 10, 22, and 23 weeks) spent some time prone (3.0, 3.5, Parental Checks 2.3, 2.2, and 1.6 hours, respectively), and 2 cot-sleeping When mothers in both groups checked their infant, it infants (aged 8 and 25 weeks) slept the entire night in usually involved touching rather than just looking at the the prone position (8.9 and 10.2 hours, respectively). infant. Table 4 shows that there was no significant dif- ference in the amount of time bed-sharing mothers Blanket Height Relative to Infant spent checking their infant compared with mothers of Results for blanket height are shown in Table 3. Infants cot-sleeping infants. Fathers/partners rarely checked the in both groups spent most of the night sleeping with the infants (data not shown), but when all of the looks and blankets below the level of the chin (bed-sharing me- touches by both parents were combined, bed-sharing dian: 7.1 hours [82% of sleep time]; cot-sleeping me- parents checked their infant a median of 11 times com- dian: 8.1 hours [100% of sleep time]). Bed-sharing in- pared with 4 checks by the parents of the cot-sleeping 1602 BADDOCK et al Downloaded from by on September 6, 2009
  • 6. TABLE 3 Blanket Height Relative to the Infant’s Face: Duration and Percentage of Sleep Time at Different Blanket Heights Blanket Height Bed Sharing, Median Cot Sleeping, Median Bed Sharing/Cot Sleeping, P (interquartile range) (interquartile range) Risk Ratio (95% CI) Below chin h/study 7.10 (5.66–9.18) 8.10 (7.28–9.42) 0.88 (0.86–0.90) .0001 % sleep timea 82 (62–99) 100 (100–100) .0001 To eyes h/study 0.83 (0–2.20) 0 (0–0) 3.12 (2.89–3.37) .0001 % sleep timea 10 (0–26) 0 (0–0) .0001 Above eyes h/study 0.20 (0–1.03) 0 (0–0) 17.06 (13.45–21.63) .0001 % sleep timea 2 (0–10) 0 (0–0) .0001 Adjusted for age, season of study, and total sleep time. CI indicates confidence interval. a Tests were negative binomial regression except those marked for Kruskal Wallis. infants (P .0001). When considering individuals, there studies resulted in very different behaviors. The study were extreme examples, for example, parents in 1 bed- showed that regular bed-share infants engaged in more sharing study checked their infant 53 times. These were feeding and more infant-mother interactions than cot- predominantly brief touches by the mother. Observa- sleep infants, side sleeping position was more common tions indicated that the bed-sharing parents did not al- during sleep and at final waking in bed-share infants, ways wake fully to check their infant, and small patting and prone sleeping position, although rare, occurred for movements, in what seemed to be drowsy sleep, were short intervals in bed-share infants, whereas it lasted all common. night for 2 cot infants. Incidents where the bedding or clothing covered the infant’s head were more common Infant Movements in the bed-sharing situation both during the night and Table 5 shows that the most common type of movement on final waking. recorded in both groups through the night was posture Previous smaller studies comparing the same practices change. Bed-sharing infants spent significantly less time have been conducted mainly in the laboratory set- in posture change movements compared with cot-sleep- ting,23,27 although attempts have been made to make the ing infants (37 vs 50 minutes, respectively). However, environment as home-like as possible. These studies the number of posture change records was similar for used a crossover design that showed that, for many both groups, suggesting that individual periods of pos- behaviors, the largest difference was recorded for regular ture change movement through the night were shorter bed sharers on their bed-share night compared with for bed-sharing infants. There were significantly fewer regular cot-sleepers on their cot-sleep night.23,27 This em- small movements (brief hand movements) by the bed- phasizes the importance of observing infants in their sharing infants, and they occurred for less total time, regular sleep arrangement, as in this study. The present whereas responses to mother were more frequent and study supports the observations from laboratory studies lasted for longer total time. Feeding was 3.7 times more that bed-share infants engage in more feeding episodes frequent in the bed-sharing group than the cot-sleeping and are checked by their mother more frequently than group. cot-sleeping infants.23,28–30 Mothers often identified ease of breastfeeding as a reason for bed sharing. Population DISCUSSION studies also support an association between bed sharing This study clearly demonstrated different behaviors of and breastfeeding31 and an association with breastfeed- both the infant and parents when comparing bed-shar- ing persisting to an older infant age.32 Several large ep- ing and cot-sleeping practices. Although the cot was idemiologic studies have shown a small but significant usually immediately adjacent to the parents’ bed, the protective effect of breastfeeding against SIDS;17,33–36 presence of the infant in the adult bed for bed-share however, this has not been shown in some others.37,38 TABLE 4 Parental Checking (looking and/or touching): Total Duration and Number of Checks for Bed- Sharing and Cot-Sleeping Infants Parental Checks Bed Sharing, Median Cot Sleeping, Median Bed Sharing/Cot Sleeping, P (interquartile range) (interquartile range) Risk Ratio (95% CI) Time mother touching, min/study 4.59 (2.58–12.25) 1.54 (0.25–3.67) 2.07 (0.99–4.55) .07 No. parental checks, no./study 11 (7–25) 4 (2–6) 3.35 (2.45–4.59) .0001 Adjusted for age, season of study, and total sleep time. CI indicates confidence interval. Negative binomial regression PEDIATRICS Volume 117, Number 5, May 2006 1603 Downloaded from by on September 6, 2009
  • 7. TABLE 5 Infant Movements and Feeding Sessions: Total Duration and Number of Movement Records for Bed-Sharing and Cot-Sleeping Infants Variable Bed Sharing, Median Cot Sleeping, Median Bed Sharing/Cot Sleeping, P (IQ range) (IQ range) Risk Ratio (95% CI) Infant movement time, min/study Small movement 1.29 (0.33–2.25) 3.17 (1.17–5.17) 0.62 (0.46–0.84) .002 Posture change 36.63 (24.58–44.92) 50.29 (36.67–66.58) 0.67 (0.54–0.83) .0001 Response to mum 3.54 (1.75–5.42) 0 (0–0) 3.88 (3.04–4.97) .0001 Number of movements, no. records/study Small movement 9 (5–15) 18 (9–25) 0.61 (0.43–0.88) .007 Posture change 108 (84–148) 127 (92–162) 0.90 (0.78–1.03) .15 Response to mum 9 (6–16) 0 (0–0) 49.80 (23.25–106.71) .0001 Feed sessions,a no.sessions/study 3 (2–4) 1 (0–1) 3.71 (2.62–5.24) .0001 Adjusted for age and season of study. CI indicates confidence interval. Movement time was analyzed using regression on log transformation of the data. Movement records were analyzed using Poisson regression. a Any feeding recommenced within 30 minutes was coded as 1 session. Cot infants were not in view when feeding, thus, feeding sessions were equated with removal from the cot. This may have overestimated feeding sessions for the cot group. Concern has been raised regarding the possibility of would be needed to check an infant in a cot, even if it accidental asphyxiation from mothers falling asleep was nearby. breastfeeding while lying down.39 No instances were The risks and/or benefits associated with increased noted where the mother was in a position that might waking have been debated. In adults and children, sleep have resulted in mechanical obstruction of the airways, fragmentation is associated with many negative effects, and no oxygen desaturation events 90% with head such as increasing the frequency and duration of ob- covered (data not given) or any increase in rectal tem- structive sleep apnea46 and increasing the arousal thresh- perature outside the reference range was observed.25 old.47,48 However, none of these studies have been con- The reason we videoed 2 nights was to establish ducted on breastfeeding women. It is not known whether there was any difference in behavior because of whether the multiple, brief, drowsy awakenings through “first-night effect” or the presence of the sensors on the the night during bed sharing would have more or less infant. Using Bland-Altman plots,40 we found no signif- impact on the mother than the few, full awakenings icant difference on key behavioral indices, such as sleep required to attend to an infant in the cot. Interestingly, time, number of infant movements per hour, feeds, and mothers in this study, as in others, report “increased sleep position, suggesting that attachment of the sensors sleep” as a reason to bed share, along with “having a did not have a significant effect on sleep behavior. more settled infant.” Studies investigating the effect of Although there is no direct evidence that increased mild sleep deprivation on infants report a possible in- maternal checking reduces SIDS, mothers in this study creased propensity to upper airway obstruction49,50 and and others2,23,41,42 report an emotional benefit from bed changes in autonomic control of cardiac function.51 sharing, because they can easily check their infant. However, it is likely that experimentally induced sleep Mothers have also been observed to actively check and deprivation has different physiologic manifestations modify infant temperature by rearranging bedding.43 from infant-initiated awakenings through the night as- Room sharing compared with infant sleeping in a sepa- sociated with breastfeeding. rate room is protective against SIDS14,15,44 and may be The finding in this study that the side sleep position related to increased maternal checks. It is likely that the was the most common sleep position for bed-share in- dramatic reduction in the multivariate relative risk for fants is in agreement with Ball’s findings.30 However, infants not sharing the room and prone from 16.99 whereas bed-share infants had significant periods of side (95% CI: 10.43–27.69) to 3.28 (95% CI: 2.06 –5.23) for sleep in laboratory-based studies,23,52 the supine position infants sharing the room and prone44 is explained by was predominant. The increased instrumentation for re- increased awareness and checking of infants while they cording electroencephalogram, electro-oculogram, and are asleep. In our study, whereas bed-share parents electromyogram in these 2 studies might have affected checked their infant more often, many of these checks the position mothers placed their infant to sleep (Helen were brief, involving minimal disruption to the mother’s Ball, PhD, written communication, 2002). The side sleep sleep. These findings are confirmed by Mosko et al,45 position has been identified as increasing the risk of who reported that total sleep time of mothers was not SIDS,15,53 reportedly associated with the tendency of decreased on bed-share nights compared with infant side-sleep infants to roll prone.15 However, the evidence cot-sleep nights and that maternal awakenings were for for this has been established from infants sleeping in a shorter duration on the bed-share nights. It is likely that cot. There is no data to establish the risk of this position greater arousal and more disruption to maternal sleep during bed-share sleep. In our study, 12 cot-sleep infants 1604 BADDOCK et al Downloaded from by on September 6, 2009
  • 8. spent some time sleeping on their side, but none were were at low risk of SIDS, because there were very few observed to roll to the prone position. All 38 of the maternal smokers, all of the infants in the bed-sharing bed-share infants slept some time on their side, and 1 group were breastfed, most mothers had some form of infant, aged 23 weeks, was observed to roll to the prone tertiary education, and families actively chose to bed position when the mother moved away from the infant. share because of perceived advantages to themselves and A characteristic sleep position of mother and breastfed their infant. The findings may be quite different in bed- infant that seems to prevent rolling has been described: sharing families where many SIDS risk factors are prev- mother sleeping in a lateral position, facing the infant, alent13,17,62 and breastfeeding is not common. with her knees drawn up under the infant feet and the Although this study has identified potential hazards mother’s arm positioned above the infant’s head.54,55 that may be encountered during bed sharing, for exam- This was observed in our study, but it was not universal, ple, head covering, it has also identified many potential despite all of our mothers being breastfeeders. benefits, for example, increased parental checks. This Head covering by blankets occurred more often in the was not a surprising finding, because in many societies bed-share group, a finding also observed by Ball (Helen around the world, bed sharing is the preferred sleep Ball, PhD, written communication, 2002) but not re- arrangement. It is only relatively recently that white ported by others. Young23 found no instances of head societies have moved to a solitary sleep arrangement, and body completely covered by bedding. This may re- where conditioning infants to sleep through the night flect a difference in home monitoring compared with the without waking is a goal valued by society.63 However, sleep laboratory, where arguably parents are more re- there is a growing trend among whites to choose to bed laxed and more likely to engage in usual practices. share as a parenting style.7–9 Whether this behavior places these infants at risk is This study has highlighted many factors that seem to another question. Being found with head covered has be common to both bed-sharing and cot-sleep infants been reported in several studies as increasing the risk of but in fact vary in important ways because of the differ- SIDS (odds ratio: 12.5; 95% confidence interval: 6.47– ent physical environments and the presence of adults. 24.1).15 Although head covering was common among Thus, risk factors identified for infants sleeping in a cot, the bed-share infants in this study, only a quarter of for example, side sleep, may not be directly applicable to infants with head-covering episodes during the night bed-sharing infants and require investigation by epide- ended up with head covered at the end of sleep. Bedding miologic studies using cases and controls in the bed- tended to be moved on and off infants more often during share environment. Secondly, the benefits of bed the natural course of sleep through the night. This may sharing, for example, increased maternal checking, help explain why bed-share infants are found with the breastfeeding, and faster and more frequent maternal head covered at the end of sleep less often than cot-sleep responses, rely on the mother’s ability to arouse, at least infants.56 Infants in the present study often stayed (with- partially, and respond to the infant through the night. out significant movement) in the head-covered position Mothers impaired, for example, by alcohol or extreme for long periods of time (eg, 3.5 hours by 1 infant), overtiredness, may not be able to respond appropriately, suggesting they were not uncomfortable. Our previous thus stressing the importance of a healthy, nonimpaired studies suggest that the risk of significant rebreathing mother in the bed-share partnership. into bedding depends on the type and thickness of cov- ering,57,58 as well as the ability of the infant to mount ACKNOWLEDGMENTS both a respiratory and arousal response. Because infants We thank Charrissa Makowharemahihi and Amanda of smoking mothers may well be the infants least likely Phillips for research assistance, Christine Rimene for to respond to this stress,59–61 the large interaction be- advice on cultural aspects, Paul Bennington and Gordon tween smoking and bed sharing noted in epidemiologic Yau for assistance with customising the database for studies may be explained by poor responsiveness to this video logging, and the families that participated in the particular occurrence during bed-sharing sleep. study. Bed-share infants in this study had a different pattern This study was supported by a grant from the Health of movements than the cot infants. Although there were Research Council of New Zealand. the same numbers of posture change episodes in both groups, episodes were shorter in the bed-share group, REFERENCES resulting in a highly significant, reduced total posture 1. McKenna JJ, Mosko S. 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  • 11. Differences in Infant and Parent Behaviors During Routine Bed Sharing Compared With Cot Sleeping in the Home Setting Sally A. Baddock, Barbara C. Galland, David P.G. Bolton, Sheila M. Williams and Barry J. Taylor Pediatrics 2006;117;1599-1607 DOI: 10.1542/peds.2005-1636 Updated Information including high-resolution figures, can be found at: & Services References This article cites 57 articles, 17 of which you can access for free at: Citations This article has been cited by 5 HighWire-hosted articles: les Subspecialty Collections This article, along with others on similar topics, appears in the following collection(s): Premature & Newborn n Permissions & Licensing Information about reproducing this article in parts (figures, tables) or in its entirety can be found online at: Reprints Information about ordering reprints can be found online: Downloaded from by on September 6, 2009