Transcript Document

Parent-infant bed-sharing:
good or bad for babies?
George Haycock
Scientific Advisor
Foundation for the Study of Infant Deaths
Co-sleeping practices generally
agreed to be dangerous
• Co-sleeping in a chair, couch or sofa
• Bed-sharing if:
– mother is a smoker
– mother has consumed alcohol (>2 units)
– mother has taken sedative drugs
– mother is excessively tired
– the infant was premature or low birth weight
Bed-sharing: claimed advantages
• Reinforcement of breast feeding
• Promotion of mother-child bonding
• Improved quality of sleep
– mother
– infant
• Higher levels of arousability
– mother
– infant
Bed-sharing: possible hazards or
disadvantages
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Increased risk of SIDS
Increased risk of overlying or suffocation
Overheating
Poorer quality of sleep
Does bed-sharing lead to improved
breast feeding rate and duration?
• Numerous studies have shown a definite
correlation between breast feeding and
bed-sharing
• It is very difficult to determine if this is
because bed-sharing encourages breast
feeding or because when women stop
breast feeding they also stop bed-sharing
Does bed-sharing increase the risk
of SIDS if mother is a non-smoker?
• Several studies from the UK and New Zealand found
increased risk if mother was a smoker but not if she was a
non-smoker
– Scragg et al 1993; Fleming et al 1996; Mitchell et al 1997; Blair et al 1999
• Other studies have suggested that there is a risk even if
mother is a non-smoker, albeit much less than if she
smokes
– Carpenter RG et al 2004; Tappin D et al 2005; McGarvey C et al 2006
• One study suggests that bed-sharing with persons other
than parents (e.g. siblings) is a risk but not sharing with
parents alone
– Hauck FR et al 2003
The ECAS Study
Carpenter RG et al. Lancet 363: 185-191, 2004
The ECAS Study
Carpenter RG et al. Lancet 363: 185-191, 2004
The ECAS Study
Carpenter RG et al. Lancet 363: 185-191, 2004
Carpenter noted that use of a duvet, and/or being found with the
head covered, were not included in the multivariate analysis that
resulted in the figures shown in Table 2. Because both of these
might be associated with bed-sharing, he therefore reanalysed the
data in a somewhat reduced data set in which this information was
available, primarily to see whether including these variables
removed the significance of the risk of bed-sharing for non-smoking
mothers.
He also noted that the control group, i.e. the babies who did not
bed-share, consisted of babies who were in their own cots either in
the parents’ room or in a room of their own. Since the latter is
known to be a risk factor compared with babies sleeping in a cot in
their own rooms (OR 3.1), this was also included in the model.
The ECAS Study
Carpenter RG et al. Lancet 363: 185-191, 2004
Age (wks)
OR
Lower CI
Upper CI
2
4
6
6.56
5.91
5.31
2.14
2.06
1.96
20.1
16.9
14.4
8
10
12
16
4.78
4.31
3.88
3.14
1.84
1.71
1.56
1.25
12.4
10.8
9.6
7.9
20
26
2.54
1.85
0.94
0.57
6.9
6.1
The ECAS Study
Carpenter RG et al. Lancet 363: 185-191, 2004
The ECAS Study
Carpenter RG et al. Lancet 363: 185-191, 2004
The ECAS Study
Carpenter RG et al. Lancet 363: 185-191, 2004
McGarvey C et al (2003) Factors relating to the infant’s last
sleep environment in sudden infant death syndrome in the
Republic of Ireland. Arch Dis Child 88:1058-1064
• Co-sleeping was found to be a risk for babies of nonsmoking mothers aged less than 16 weeks (Irish
infants 1994-98: 152 cases, 620 controls).
• In this study as published, the co-sleeping group
included both bed- and sofa-sharers.
• A further, so far unpublished, analysis was performed
on an expanded data set (1994-2001) in which sofa
sleepers were excluded. A significant risk was found for
babies of non-smoking mothers aged under 16 weeks,
OR 6.2: CI 1.88-20.61 (McGarvey C, personal
communication).
McGarvey C et al (2006) An 8 year study of risk factors for SIDS: bedsharing versus non-bed-sharing. Arch Dis Child 91:318-323
• The odds ratio for SIDS for bed-sharing infants
whose mothers had smoked during pregnancy
was 13.87 (9.58-20.09)
• The odds ratio for SIDS for bed-sharing infants
whose mothers had not smoked during
pregnancy was 2.09 (0.98-4.39)
• Bed-sharing remained a significant risk for
babies aged 10 weeks or less after adjustment
for maternal smoking
Tappin D et al. (2005) Bedsharing, roomsharing and sudden infant
death syndrome in Scotland: a case-control study. J Pediatr 147: 32-37
A 1:2 case control study including 123 infants who died of SIDS
between January 1 1996 and May 31 200, and 263 controls. Main
outcome measure: sharing a sleep surface during last sleep
Tappin D et al. (2005) Bedsharing, roomsharing and sudden infant
death syndrome in Scotland: a case-control study. J Pediatr 147: 32-37
• The highest risk was associated with
couch sharing: OR 66.9 (2.8-1,596)
• Authors’ conclusions:
– Bedsharing is associated with an increased
risk of SIDS for infants <11 weeks of age.
Sharing a couch for sleep should be strongly
discouraged at any age
Developmental Psychobiology 40: 14-22, 2002
Hunsley M, Thoman EB
Developmental Psychobiology 40: 14-22, 2002
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101 infants enrolled (45 male) at age 4 weeks
Studied twice, at 5 weeks and 6 months
Each study lasted 12 hours (7 pm – 7 am)
Motility Monitoring System
– Thin, pressure sensitive pad placed on the mattress
– Signals sent via an amplifier to a 24 hour data logger
Hunsley M, Thoman EB
Developmental Psychobiology 40: 14-22, 2002
• Infants classified as:
– Long term co-sleepers
• Co-sleeping twice a week or more for at least 6 months
– Short term co-sleepers
• Co-sleeping twice a week or more for less than 6 months
– Non-co-sleepers
• Co-sleeping less than twice a week or not at all
Hunsley M, Thoman EB
Developmental Psychobiology 40: 14-22, 2002
• Sleep/wake variables studied
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–
–
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Active sleep (AS)
Quiet sleep (QS)
Waking (W)
Active sleep bout length
• Mean duration of AS bouts during the recording
– Quiet sleep bout length
• Mean duration of QS bouts during the recording
– Arousals in active sleep
– Arousals in quiet sleep
Hunsley M, Thoman EB
Developmental
Psychobiology
40: 14-22, 2002
Hunsley M, Thoman EB
Developmental Psychobiology 40: 14-22, 2002
• Compared with non-co-sleepers, at 5 weeks and
6 months:
– Long term co-sleepers showed:
• More QS
• Longer bouts of QS
• At 6 months:
– Long term co-sleepers showed:
• Less AS
• Fewer arousals in AS
• Less W
• Short term co-sleepers behaved in an
intermediate way between long term co-sleepers
and non-co-sleepers
Hunsley M, Thoman EB
Developmental Psychobiology 40: 14-22, 2002
• These patterns, obtained during non-co-sleeping,
were in marked contrast to the patterns seen
during actual co-sleeping
• Co-sleeping infants showed:
– Less QS
– More arousals in QS
– More sleep-stage shifts
• This pattern has been called sleep fragmentation
– Kahn et al 1988; Roehrs et al 1994; Thoman & Whitney 1989
• Thus co-sleeping infants show extremes of sleep
behaviour according to whether they are cosleeping at the time or not
Hunsley M, Thoman EB
Developmental Psychobiology 40: 14-22, 2002
• “Sleep fragmentation has been consistently
associated with adverse conditions or consequences
at all ages including:
– Illness
– Poor performance on cognitive tests
– Negative developmental outcome”
• Anders & Roffwarg, 1973
• Bonnet, 1986
• “This outcome could be expected as the result of the
stress of repeated disruptions of an infant’s sleep
that occur throughout periods of co-sleeping”
Parent-infant bed-sharing:
good or bad for babies?
• Conclusions (1)
– A beneficial effect on breast feeding is possible but
unproven
– There is a very large increase in risk of SIDS
associated with couch or sofa sharing
– There is a substantial increase in risk of SIDS for bedsharing infants of smoking mothers
– There is a much smaller, but probably significant,
increase in risk of SIDS for bed-sharing infants of
non-smoking infants at least in the first 2-3 months
– The different sleep patterns seen in bed-sharing
infants as compared with non-bed-sharing infants are
not necessarily advantageous to the infant
Parent-infant bed-sharing:
good or bad for babies?
• Conclusions (2)
– The advice currently given by the Foundation
for the Study of Infant Deaths, that the safest
place to sleep your baby for the first 2 to 3
months of life is in a separate cot in the
parents’ bedroom, is justified by available
evidence
– It is certainly acceptable to take the baby into
the mother’s bed to breast feed, but it is
safest to return the baby to the cot after
feeding
Dangers of the ‘Null Hypothesis’
• “Unfortunately any method which invites
the contemplation of a ‘null’ hypothesis is
open to grave misuse, or even abuse, and
this seems particularly so in the social
sciences, where high standards of
objectivity are especially difficult to obtain,
and data often of dubious quality”
– Edwards AWF. Likelihood. Cambridge 1972
Dangers of the ‘Null Hypothesis’
• “What used to be called judgement is now
called prejudice, and what used to be
called prejudice is now called a null
hypothesis. In the social sciences,
particularly, it is dangerous nonsense
(dressed up as ‘the scientific method’),
and will call much trouble before it is
widely appreciated as such”
– Edwards AWF. Likelihood. Cambridge 1972