review article is bed sharing beneficial and safe during

Review ArticleIs ‘‘Bed Sharing’’ Beneficial and Safe during Infancy?A Systematic Review

Rashmi Ranjan Das,1 M. Jeeva Sankar,2 Ramesh Agarwal,2 and Vinod Kumar Paul2

1 Department of Pediatrics, All India Institute of Medical Sciences, Bhubaneswar 751019, India2Newborn Health and Knowledge Centre (NHKC), Department of Pediatrics, All India Institute of Medical Sciences,New Delhi 110029, India

Correspondence should be addressed to Ramesh Agarwal; [email protected]

Received 5 October 2013; Accepted 25 November 2013; Published 30 January 2014

Academic Editor: Namık Yasar Ozbek

Copyright © 2014 Rashmi Ranjan Das et al. This is an open access article distributed under the Creative Commons AttributionLicense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properlycited.

Background. There is conflicting evidence regarding the safety and efficacy of bed sharing during infancy—while it has been shownto facilitate breastfeeding and provide protection against hypothermia, it has been identified as a risk factor for SIDS. Methods. Asystematic search of major databases was conducted. Eligible studies were observational studies that enrolled infants in the first4 weeks of life and followed them up for a variable period of time thereafter. Results. A total of 21 studies were included. Thoughthe quality of evidence was low, bed sharing was found to be associated with higher breastfeeding rates at 4 weeks of age (75.5%versus 50%, OR 3.09 (95% CI 2.67 to 3.58), 𝑃 = 0.043) and an increased risk of SIDS (23.3% versus 11.2%, OR 2.36 (95% CI 1.97 to2.83), 𝑃 = 0.025). Majority of the studies were from developed countries, and the effect was almost consistent across the studies.Conclusion. There is low quality evidence that bed sharing is associated with higher breast feeding rates at 4 weeks of age and anincreased risk of SIDS. We need more studies that look at bed sharing, breast feeding, and hazardous circumstance that put babiesat risk.

1. Background

In olden days, mothers and babies were separated after birthto prevent infectious diseases and to keep newborns in a safeand controlled environment. The practice of “rooming-in”(keeping the mother and the baby in same room) startedwhen it was realized that the separation had serious impli-cations for the emotional and psychological development ofboth mothers and newborns [1]. Rooming-in is now rec-ommended by the World Health Organization (WHO) andUNICEF as part of the Baby Friendly Hospital Initiative(BFHI) programme to promote breastfeeding [2].

During rooming-in, the infant is placed close to themother either by bed sharing, by an attached side-car crib,or by her bedside in a standalone cot. Of these, the “ideal”methodwould be “bed sharing” in which the newborn is kepton the same bed as that of the mother. The “bed sharing”behavior, however, is controversial in public health parlance.

Some consider it a significant risk factor for sudden infantdeath syndrome (SIDS) and argue for its wholesale elimi-nation [3–5]. Others disagree, finding little or no scientificevidence for an associationwith SIDS, except among smokingmothers [6–8].

When research into SIDS began in the 1980’s, researchershad little idea of why these babies died. In the 1990’s, bedsharing related to infant sleeping environment was identifiedas one of the risk factors. By the end of this decade, a strongerinteraction between bed sharing and smoking was observed.One recent study exposed an interaction between bed sharingand alcohol/drugs [9]. This study also partially explained thedifference in SIDS rates between cultures where cosleepingis the usual practice. Bed sharing is common in certaincultures where the prevalence of SIDS is high, including theAfrican black populations in the United States, Maori, andAboriginal populations. Bed sharing is common in certaincultures where the prevalence of SIDS is low, including Asian

Hindawi Publishing CorporationInternational Journal of PediatricsVolume 2014, Article ID 468538, 16 pageshttp://dx.doi.org/10.1155/2014/468538

2 International Journal of Pediatrics

communities (Japan, Hong Kong, Bangladesh, and thosein UK) and Pacific Islander communities in New Zealand.Actually, it is not the bed sharing that distinguishes thesecultures, but other factors (e.g., smoking and use of alcohol/drugs) which in conjunction with cosleeping may put infantsat risk [9].

With this background, we conducted present systematicreview to evaluate the efficacy and safety of bed sharing com-pared to no bed sharing during infancy, to provide updatedevidence to the World Health Organization (WHO) which isin the process of reviewing its recommendations on postnatalcare of new born infants and their mothers.

2. Methods

2.1. Types of Studies. We intended to include randomizedand quasirandomized trials that compared bed sharing ofmothers and their infants with no bed sharing. If randomizedstudies were not available, we planned to include observa-tional studies after applying the following eligibility criteria:

(1) cohort studies that enrolled infants in the first 4 weeksof life and followed them up for a variable period oftime thereafter were included;

(2) case-control studies in which

(i) infants being exclusively breastfed at 4–6wk/3-4 months/6 months of age or those who died ofSIDS were the “cases”;

(ii) the exposure (i.e., bed sharing) occurred in theneonatal period for at least a few “cases”; ifthis is not explicitly mentioned in the study, weassumed this if the study had reported the expo-sure status, that is, bed sharing, as a “routine”or “usual” practice;

(3) studies that did not include neonates and measuredthe exposure in the “last sleep” were excluded;

(4) cross-sectional studies that measured the associationbetween breastfeeding status at different time pointsand bed sharing starting from the neonatal perioduntil 1 year of age were included.

We excluded the studies on “rooming-in” if they had notreported bed sharing separately. When there were multiplepublications from one study, only the publication with themost relevant information to the systematic review was used.

2.2. Exposure or Intervention. Bed sharing of mother and herneonate was the exposure studied. Terminology regardingbed sharing, room sharing, and cosleeping used both in thescientific literature and the popular literature is inconsistentand potentially problematic. For the purposes of this paper,“bed sharing” term was used if the newborn was kept on thesame bed as that of the mother.

2.3. Outcome Measures and Their Definitions. The primaryoutcomes were the (a) proportion of infants being breastfed(any or exclusive) at 4–6wk, 3-4 months, and 6 months of

age and (b) proportion of infants dying of SIDS in the firstyear of life. The secondary outcomes were the incidence ofhypothermia, all-causemortality during neonatal period, andincidence of neonatal sepsis.

Exclusive breastfeeding was defined as an infant receivingonly breast milk with no additional foods or liquids, not evenwater except multivitamin supplements or medications, andany breastfeeding means that an infant receives any amountof breast milk regardless of supplements. SIDS was definedas the unexplained death without warning of an apparentlyhealthy infant usually during sleep. Hypothermia was definedas skin temperature <36.5∘C. Neonatal mortality referred todeaths due to all causes occurring in the first 28 days ofpostnatal life while neonatal sepsis was defined as the clinicalsyndromeof bacteremiawith systemic signs and symptoms ofinfection in the first 28 days of postnatal life with or withoutculture positivity.

2.4. Search Methodology. The following databases weresearched independently by three review authors (RashmiRanjan Das, Ramesh Agarwal, M. Jeeva Sankar) using thesearch terms (newborn OR infant OR neonat∗) and (room-ing-in OR bedding-in OR bed share OR bed sharing ORcosleeping OR sleeping). The databases searched were andMEDLINE via PubMed (1966–May 2013), Cochrane CentralRegister of Controlled Trials (CENTRAL, The CochraneLibrary, Issue 6, May 2013), and EMBASE (1988–May 2013).Searches were limited to human studies. There were nolanguage restrictions. For further identification of ongoingtrials, the website http://www.clinicaltrials.gov/ was searchedand relevant trials were screened for eligibility of inclusion inthe review. We also checked the cross-references of relevantarticles. We treated side-car crib exposure (used in somestudies) as no bed sharing.

2.5. Data Extraction. Data extraction was done using astandardized data extraction form that was designed andpilot tested a priori. Three authors (Rashmi Ranjan Das, M.Jeeva Sankar, and Ramesh Agarwal) independently extracteddata from included studies, including year, setting (country,type of population, socioeconomic status, baseline neonatalmortality, baseline practice of rooming-in or bedding-in,gestation, and birth weight of infants), exposure/intervention(bed sharing, routine or last night), and results (outcomemeasures, effect, significance). Disagreements in extracteddata were resolved through discussion.

2.6. Assessment of Risk of Bias in Included Studies. Two reviewauthors (M. Jeeva Sankar, RashmiRanjanDas) independentlyassessed the methodological quality of the selected studies.Quality assessment was undertaken using the NewcastleOttawa Scale (NOS) for observational studies. This scaleassesses the quality under three major headings, namely,selection of the studies (representativeness, exposure assess-ment/control selection), comparability (adjustment formain/additional confounders), and outcome/exposure (adequacyof outcomemeasured, exposure measured versus self-report)[10]. Any disagreement was resolved through discussion withthe third author (Ramesh Agarwal).

International Journal of Pediatrics 3

Records identified through databasesearchingPubMed = 3739

Central = 548

EMBASE = 4726

Records after removal ofduplicates: N = 8748

Records excluded scanning the title and/orabstract: N = 8563

Full-text articles assessed: N = 185

Records excluded: N = 164

Intervention/exposure not studied (N = 80)Outcome not reported (N = 20)No control arm (N = 54)Duplicate publication (N = 10)

Studies included in qualitative analysis: N = 21

SIDS and bed share = 14; breastfeeding and bedshare = 8 (one study reported both outcomes)

Studies included in quantitative analysis: N = 15

Figure 1: Flow of studies.

2.7. DataAnalysis. For each outcomemeasure, the total num-ber of participants and the number of participants experi-encing the event and the adjusted odds ratio (aOR) providedby the study authors were extracted. We intended to useonly aOR for pooling the results. If adjusted ratios were notprovided in a given study, we used the unadjusted OR.

Meta-analysis was done by the generic inverse varianceusing the user written command “metan” in Stata 11.2 (Stata-Corp, College Station, TX). We used the natural logarithmconverted values of aOR and their confidence intervals(CI) for computing the pooled estimates. The heterogeneitybetween the studies was quantified by using a measure of thedegree of inconsistency in their results (𝐼2 statistic). Giventhat all the included studies were observational and had aninherent risk of heterogeneity between them, we planned touse fixed-effect model for pooling their results irrespective ofthe degree of heterogeneity. For the outcome of breastfeedingstatus, we planned to have only one summary result—breastfeeding status at 4 to 6 weeks of age.

3. Results

We identified 9013 articles, of which 21 were found to beeligible for inclusion (breastfeeding and bed sharing = 8; SIDSand bed sharing = 13; one study reported both the outcomes)(Figure 1) [9, 11–30]. A total of 15 studies provided data for thequantitative analysis (Tables 1 and 2) [9, 13, 14, 19–30]. Noneof the included studies were randomized trials (RCTs), as we

could not find any RCT that specifically studied the interven-tion (bed sharing). The 13 studies [9, 19–30] that evaluatedSIDS and bed sharing were case-control studies while amongthe 8 studies reporting breastfeeding rate, one was case-control study [12], and the other seven were cross-sectionalstudies [11, 13–18]. All except three studies [12, 14, 15] werepopulation based. Studies reporting SIDS included 13072infants and provided data up to 2 years of age while thosereporting breastfeeding included 25276 infants and provideddata up to 1 year of age. Majority of the included studies wereof good quality as per the New Castle Ottawa Scale (Table 3).

3.1. Breastfeeding. Only one study reported exclusive breast-feeding rateswhile the others reported any breastfeeding rates[15]. Mailed questionnaires were used to collect data in allstudies except one which used face-to-face interview [15]. Allexcept the one studywere fromdeveloped countries [15]. Lossto follow-up rate varied from 2.2% to 50% in the includedstudies.The risk of bias in these studies was moderate to high(Table 1). Almost all the studies showed a consistent beneficialeffect on any/exclusive breastfeeding rates at the three differ-ent time points, that is, at 4 to 6 weeks, 3 to 4 months, andat 6 months of age. The effect sizes of the individual studiesvaried from 1.5 to 6.7 (Table 1). We could pool the results oftwo studies that reported breastfeeding rates at 4–6 weeksof age [13, 14]. Pooled analysis showed 3-fold odds of beingexposed to bed share during the neonatal period in those whowere breastfed compared to those who were not (pooled OR


Table1:Observatio

nalstudies

onbedsharea

ndbreastfeeding.

S.no

.Stud

yID

/site

orcoun

try

Design,

setting

Stud

ypo

pulatio

nNum

bero

fsub

jects

Interventio

n/expo

sure

Outcome(effectsize)

Com

ments

1Flicketal.

2001/U

SA[11]

Cross-sectionalstudy

(with

inan

interventio

nalstudy),

popu

latio

nbased

Pregnant

wom

enenrolledat28

wk,

contactedatarou

nd8

weeks

after

delivery

Question

naire

based

survey

of218

consecutiveinfants

Bedshare

Breastfeedingrate=61/13

3(bed

share),

30/85(nobedshare)

OR(95%

CI):1.5

5(0.86,2.84)

Any

breastfeeding(not

exclu

siveb

reastfeeding

)at8

weeks

ofage.Lo

ssto

follo

wup

was

2.2%

.

2Ba

ll2003/U

nited

Kingdo

m[12]

Case-con

trolstudy,

popu

latio

nbased

Health

infantsa

ndmothers,delivered

at36+weeks.Followed

uptill4

mon

thso

fage

Cases,112

Con

trols,

141

Bedshare


2(case),

54/14

1(control)

OR(95%

CI):4.2(2.38,7.4

7)

Any

breastfeeding(not

exclu

siveb

reastfeeding

)for

≥1m

oisthed

efinitio

nof

the

case.L

osstofollo

wup

was

40%.

3Blaira

ndBa

ll2004/U

nited

Kingdo

m[13]

Datafrom

two

studies:one

was

cross-sectionaland

theo

ther

was

long

itudinal,

popu

latio

nbased

Health

yinfantsa

ndtheirm

othersatho

me

Dataa

vailableo

n424

subjects

Bedshare

Breastfeedingrateat4weeks

=73/84(bed

share),113/227

(nobedshare)

OR(95%

CI):6.66

(3.37

,13.3)

Repo

rted

anybreastfeeding

(not

exclu

siveb

reastfeeding

rate).Lo

ssto

follo

wup

was

<20%

Breastfeedingrateat3

mon

ths=

58/74(bed

share),

202/350(nobedshare)

OR(95%

CI):2.66

(1.43,5.14)

4McC

oyetal.

2004/U

SA[14

]Cr

oss-sectionalstudy,

commun

itybased

(follo

wup

atho

meo

finstitu

tionalbirths)

Datafrom

theInfant

Care

Practic

esStud

y(ICP

S)betweenyears

1995

and1998.

Follo

wup

ofinfants

born

atselected

study

hospita

ls

Dataa

vailableo

n10355

subjects

Bedshare

Breastfeedingrateat1m

onth

=1346

/2071(bedshare),

4142/8284(nobedshare)

Adjuste

dOR(95%

CI):3.0

(2.6,3.5)

Repo

rted

anyBF

ratefor>

4weeks.L

osstofollo

wup

was

∼30%

Breastfeedingrateat3m

onths

=725/1346

(bed

share),

3107/900

9(nobedshare)

Adjuste

dOR(95%

CI):3.4

(2.9,

4.0)

Breastfeedingr

atea

t6mon

ths

=518/1243

(bed

share),

2071/9112(nobedshare)

Adjuste

dOR(95%

CI):3.6(3,

4.2)

5Lahr

etal.

2007/U

SA[15]

Cross-sectionalstudy

(rando

msample

survey),po

pulatio

nbased

Stratifi

edsampleo

fwom

endraw

neach

mon

thfro

mrecently

filed

birthcertificates

betweenyears1998

and1999

Dataa

vailableo

n1685

subjects

Bedshare


(bed

share),

770/110

1(no

bedshare)

Adjuste

dOR(95%

CI):2.65

(1.72to

4.08)

Any

breastfeeding

for>

4weeks


Table1:Con

tinued.

S.no

.Stud

yID

/site

orcoun

try

Design,

setting

Stud

ypo

pulatio

nNum

bero

fsub

jects

Interventio

n/expo

sure

Outcome(effectsize)

Com

ments

6

Blaire

tal.

2010/U

nited

Kingdo

m[16]

Prospective

long

itudinalstudy,

popu

latio

nbased

Infantso

fallpregnant

wom

enresid

ingin

the

3health

distr

ictsof

Avon

;age

grou

p:birth

to4years.Be

dshare

was

categoriz

edinto

thefollowing3

grou

ps:early,

late,and

constant

Dataa

vailableo

n7447

subjects

Bedshare


mon

ths=

733/1415

(con

stant

andearly

bedshare),2111/6

032

(nobedshare)

OR(95%

CI):2.0(1.77to2.25)

Repo

rted

onlybreastfeeding

rate(not

exclu

siveb

reast

feedingrate).Th

eadjustedOR

forb

edsharingin

then

eonatal

ageg

roup

isno

tkno

wn.

Loss

tofollo

wup

was

50%loss.


mon

ths=

322/1415

(con

stant

andearly

bedshare),549/6032

(nobedshare)

OR(95%

CI):2.94

(2.52

to3.44

)

7Tan2011/M

alaysia

[17]

Cross-sectionalstudy,

facilitybased

Mother-infant

pairs

with

infantsu

pto

6mon

thsa

ttend

ing

health

clinics

over

4mon

thsinyear

2006

Dataa

vailableo

n682

subjects

Bedshare


(bed

share),

45/18

1(no

bedshare)

Adjuste

dOR(95%

CI):1.5

0(1.12

to2.37)

Exclu

siveb

reastfeeding

rate

onem

onth

priortointerview.

Only20.3%of

study

infants

were<1m

oof

age—

datafor

thissubgroup

isno

tkno

wn.

Lossto

follo

wup

was<5%

8Mollborgetal.

2011/Sweden

[18]

Cross-sectionalstudy,

popu

latio

nbased

Rand

omlyselected

families

with

infants

who

hadreached6

mon

thso

fage

Question

naire

based

survey

on8176

families

Bedshare


(bed

share),

159/2167

(nobedshare)

Adjuste

dOR(95%

CI):1.9

4(1.56to

2.41)

Any

breastfeeding(not

exclu

siveb

reastfeeding

)at6

mon

thso

fage.L

ossto

follo

wup

was

31.5%


Table2:Observatio

nalstudies

onbedsharea

ndSIDS.

S.no

.Stud

yID

/cou

ntry

Design,

setting

Stud

ypo

pulatio

nNum

bero

fsub

jects

Interventio

n/expo

sure

Outcome

Com

ments

1Klono

ff-Coh

enandEd

elstein

1995/U

SA[19

]

Case-con

trolstudy,

popu

latio

nbased

Cases:allinfantsfro

mbirthto

1yearo

fage

died

ofSIDS;controls:

matched

forb

irth

hospita

l,sex,race,dateo

fbirth,andthes

ames

urvey

Cases,200

Con

trols,

200

Bedshare

SIDSrate=60/200

(case),52/200(con

trol)

Noseparatedataforn

eonates.

Thes

tudy

repo

rted

theo

ddsfor

bedsharingdu

ringthed

aytim

ealso

(wed

idno

tuse

thatdata).

ORadjuste

dforp

assiv

esmok

ing.

Lossto

follo

wup

was

25%

2Broo

keetal.

1997/Scotland

[20]

Case-con

trolstudy,

popu

latio

nbased

Cases:allinfantd

eaths

occurringfro

m7thdayof

lifeto1y

ear;controls:

births

immediatelybefore

andaft

ertheind

excase

inthes

amem

aternityun

itandmatched

forthe

same

survey

Cases,146

Con

trols,

275

Bed-share

SIDSrate=11/14

6(case),

6/275(con

trol)

Noseparatedataforn

eonates

available.Other

factorsstudied,

GA≤36

wks,B

W<2500

g.Lo

ssto

follo

wup

was

25%

3L’H

oire

tal.

1998/Th

eNetherla

nds[21]

Case-con

trolstudy,

popu

latio

nbased

Cases:allsud

dendeaths

from

7days

to2yearso

fage;controls:

matched

for

dateof

birthandthes

ame

survey

Cases,73

Con

trols,

146

Bed-share

SIDSrate=6/73

(case),

7/146(con

trol)

Out

of73

SIDS,on

ly10

happ

ened

durin

gthen

eonatalp

eriod.

Other

factorsstudied:smok

ing,

alcoho

l.Datap

rovidedfor

infantsw

howeren

otexpo

sedto

passives

mok

ing

4Blaire

tal.

1999/U

nited

Kingdo

m[22]

Case-con

trolstudy,

popu

latio

nbased

Cases:allu

nexp

ected

deaths

upto

2yearso

fage;controls:

infantsb

orn

immediatelybefore

and

after

theind

excase

and

matched

forthe

same

survey

Cases,321

Con

trols,

1299

Bed-share

SIDSrate=82/321

(case),189/12

99(con

trol)

Separatedataforn

eonatesn

otavailable.Other

factorsstudied:

smok

ing,alcoho

l.Only2

3infants

died

between7and60

days

oflife

5Arnestadetal.

2001/N

orway

[23]

Case-con

trolstudy,

popu

latio

nbased

Cases:allsud

dendeaths

amon

gchild

renbetween

the2

ndweekand3y

rsof

age;controls:

infants

matched

forsex

anddate

ofbirth,rand

omlypicked

from

then

ationalregister

andmatched

forthe

same

survey

Cases,174

Con

trols,

375

Bed-share

SIDSrate=15/17

4(case),

24/375

(con

trol)

Noseparatedataforn

eonates

available(ou

tof174

cases,on

ly13

died

before

2mon

thso

fage).

Other

factorsstudied:smok

ing,

breastfeeding,birthordera

ndweight,mod

eofsleeping,

dummyuse,andsocioecono

mic

factors.Ad

juste

dforp

assiv

esm

oking.Lo

ssto

followup

was

31%(case)and25%(con

trol)


Table2:Con

tinued.

S.no

.Stud

yID

/cou

ntry

Design,

setting

Stud

ypo

pulatio

nNum

bero

fsub

jects

Interventio

n/expo

sure

Outcome

Com

ments

6Williamse

tal.

2002/N

ewZe

aland[24]

Case-con

trolstudy,

popu

latio

nbased

Cases:allu

nexp

ected

infant

deaths

from

29days

to1y

earo

fage;con

trols:

rand

omlyselected

from

allbirths,excepth

ome

births,and

matched

for

thes

ames

urvey

Cases,369

Con

trols,

1558

Bed-share

SIDSrate=86/369

(case),162/15

58(con

trol)

Noseparatedataforn

eonates

available.Other

factorsstudied:

smok

ing,breastfeeding.Be

dsharingrefersto

“usual”

patte

rnor

lastnight’ssle

episno

tkno

wn.

Lossto

follo

wup

was

10–19%

7Carpenter

etal.

2004/Europ

e[25]

Case-con

trolstudy,

popu

latio

nbased

Cases:allu

nexplained

deaths

inthefi

rstyearo

flife;controls:

rand

omly

selected

from

theb

irth

records,matched

fora

geandthes

ames

urvey

Cases,281

Con

trols,

1760

Bed-share

SIDSrate=32/281

(case),139/17

60(con

trol)

Ofthe

total700

oddcases,on

ly57

SIDSoccurred

inthefi

rst

mon

thof

life.Other

factors

studied:smok

ing,alcoho

l.Inform

ationdepicted

here

isfor

infantsw

hose

mothersdidno

tsm

oke

8Bu

bnaitie

neetal.2005/

Lithuania[

26]

Case-con

trolstudy,

popu

latio

nbased

Cases:inclu

ded<1y

earo

fageg

roup

died

ofSIDS;

controls:

matched

ford

ate

ofbirth,region

,and

the

sames

urvey

Cases,35

Con

trols,

145

Bed-share

SIDSrate=0/35

(case),

20/14

5(con

trol)

Noseparatedataforn

eonates

available(on

ly1S

IDSdu

ringthe

neon

atalperio

d).Studied

subgroup

s,GA≤36

wks,B

W<2

500g

.Losstofollo

wup

was

22.2%in

cases

9McG

arveyetal.

2006/Ir

eland

[27]

Case-con

trolstudy,

popu

latio

nbased

Cases:allinfantsfro

mbirthto

1yearo

fage

died

ofSIDS;controls:

matched

ford

ateo

fbirth,

commun

ityarea,and

the

sames

urvey

Cases,259

Con

trols,

829

Bed-share

SIDSrate=128/259

(case),101/829

(con

trol)

Datap

rovidedisforinfantsaged

<10

weeks

ofage.Other

factors

studied:smok

ing,alcoho

l.Lo

ssto

follo

wup

was

14%

10

Ruys

etal.

2007/Th

eNetherla

nds

[28]

Case-con

trolstudy,

popu

latio

nbased

Cases:allinfants<6

mon

thso

fage

died

ofcot

deaths;con

trols:

infantso

fthes

amea

gegrou

pswho

participated

ina

coun

tryw

ides

urvey

Cases,138

Con

trols,

1628

Bed-share

SIDSrate=36/13

8(case),151/16

28(con

trol)

Noseparatedataforn

eonates

available.Other

factorsstudied:

smok

ing,breastfeeding.

Adjuste

dforb

reastfeeding

,age,

andpassives

mok

ing

11Blaire

tal.

2009/Eng

land

[9]

Case-con

trolstudy,

popu

latio

nbased

Cases:allu

nexp

ected

deaths

upto

2yearso

fage;controls:

from

the

maternitydatabase

ofon

eho

spita

land

matched

for

thes

ames

urvey

Cases,79

Con

trols,

87Be

d-share

SIDSrate=30/79(case),

17/87(con

trol)

Other

factorsstudied:smok

ing,

narcotics,GA≤37

wks,B

W<

2500

g.Neonatesa

ccou

nted

for

only15%of

SIDS.Lo

ssto

follo

wup

was

5–14%in

both

the

grou

ps


Table2:Con

tinued.

S.no

.Stud

yID

/cou

ntry

Design,

setting

Stud

ypo

pulatio

nNum

bero

fsub

jects

Interventio

n/expo

sure

Outcome

Com

ments

12

Venn

emann

etal.

2009/G

ermany

[29]

Case-con

trolstudy,

popu

latio

nbased

Cases:allinfantsfro

mbirthto

1yearo

fage

died

ofSIDS;controls:

matched

ford

ateo

fbirth

andthes

ames

urvey

Cases,333

Con

trols,

998

Bed-share

SIDSrate=27/333

(case),28/998(con

trol)

Datap

rovidedisforinfantsaged

<13

weeks

ofage.Other

factors

studied:smok

ing,GA≤37

wks,

BW<1500

g.Ad

juste

dfor

maternalsmok

ing.Lo

ssto

follo

wup

was

18–4

2%in

both

the

grou

ps

13Fu

etal.

2010/U

SA[30]

Case-con

trolstudy,

popu

latio

nbased

Cases:allinfantsfro

mbirthto

1yearo

fage

died

ofSIDS:controls:

matched

forb

irth,race,

age,birthweight,andthe

sames

urvey

Cases,195

Con

trols,

194

Bed-share

SIDSrate=15/19

5(case),

6/194(con

trol)

Repo

rted

datafor3

subgroup

s:<1m

o,1–3m

o,and>4m

o;on

lythe1stmon

thdatahasb

eenused

here.O

ther

factorsstudied:

smok

ing,alcoho

l.Be

dsharing

inclu

dedsle

epingon

them

attre

ssas

wellassofa.Lo

ssto

follo

wup

was

25%


Table3:Qualityassessmento

fincludedstu

dies

usingtheN

ewCa

stleOtta

waS

cale.

Stud

yauthor,

year,cou

ntry

Selection

Com

parabilityof

cases

andcontrolson

the

basis

ofthed

esignor

analysis

Expo

sure

Com

ment

Isthec

ase

defin

ition

adequate?

Representativ

eness

ofthec

ases

Selectionof

controls

Definitio

nof

controls

Ascertainm

ento

fexpo

sure

Thes

ame

metho

dof

ascertain-

mento

fcases

andcontrols

Non

respon

serate

Carpenter

etal.200

4,Eu

rope

[25]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,infantsm

atched

fora

geandthes

ame

survey

area,rando

mly

selected

from

the

birthrecords(∗

)

Yes,grou

pscomparable

andalso

adjuste

dfor

mostp

otentia

lconfou

nders(∗∗

)

Yes,interviews(∗

)Yes(∗

)Described

(∗)Goo

dqu

ality

Blaire

tal.

1999,U

nited

Kingdo

m[22]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,infantsb

orn

immediatelybefore

andaft

ertheind

excase

(∗)

Yes,grou

pscomparable

andalso

adjuste

dfor

mostp

otentia

lconfou

nders(∗∗

)

Yes,interviews(∗

)Yes(∗

)Described

(∗)Goo

dqu

ality

Arnestadetal.

2001,N

orway

[23]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,infantsm

atched

forsex

anddateof

birth,rand

omly

picked

from

the

natio

nalregister

(∗)

Yes,grou

pscomparable

andalso

adjuste

dfor

mostp

otentia

lconfou

nders(∗∗

)

Yes,mailed

questio

nnaire

(∗)

Yes(∗

)

Described,

31%and25%

lossforthe

casesa

ndcontrols,

respectiv

ely(∗)

Goo

dqu

ality

Bubn

aitie

neet

al.2005,

Lithuania[

26]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,infantsm

atched

ford

ateo

fbirthand

region

,rando

mly

picked

(∗)

Yes,grou

pscomparable.Not

adjuste

dform

ost

potentialcon

foun

ders

(∗)

Yes,ho

mev

isitsin

casesa

ndmailed

questio

nnaire

incontrols(∗)

No

Described

onlyforthe

cases,22.2%

loss(∗)

Goo

dqu

ality

Ruys

etal.

2007,Th

eNetherla

nds

[28]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,infantsw

hoparticipated

inanothersurvey(∗)

No,grou

psno

tcomparable.Ad

juste

dform

ostp

otentia

lconfou

nders(∗

)

Yes,ho

mev

isitsand

directinterviewin

casesa

nddirect

interviewin

controls

(∗)

Yes(∗

)Not

describ

edGoo

dqu

ality

McG

arveyet

al.2006,

Ireland[27]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,infantsm

atched

ford

ateo

fbirthand

popu

latio

nbased

area,rando

mlypicked

from

birthregiste

r(∗

)

Yes,grou

pscomparable

andalso

adjuste

dfor

mostp

otentia

lconfou

nders(∗∗

)

Yes,ho

meinterview

inbo

thcasesa

ndcontrols(∗)

Yes(∗

)Described,

14%loss(∗)

Goo

dqu

ality

Fuetal.2010,

USA

[30]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,infantsm

atched

forb

irthrace,age,

andbirthweight,

rand

omlypicked

from

birthregiste

r(∗

)

Yes,grou

pscomparable.Not

adjuste

dform

ost

potentialcon

foun

ders

(∗)

Yes,ho

mev

isitsand

directinterviewin

casesa

nddirect

interviewin

controls

(∗)

Yes(∗

)Described,

25%loss(∗)

Goo

dqu

ality


Table3:Con

tinued.

Stud

yauthor,

year,cou

ntry

Selection

Com

parabilityof

cases

andcontrolson

the

basis

ofthed

esignor

analysis

Expo

sure

Com

ment

Isthec

ase

defin

ition

adequate?

Representativ

eness

ofthec

ases

Selectionof

controls

Definitio

nof

controls

Ascertainm

ento

fexpo

sure

Thes

ame

metho

dof

ascertain-

mento

fcases

andcontrols

Non

respon

serate

Klono

ff-Coh

enand

Edels

tein

1995,

USA

[19]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,infantsm

atched

forb

irthho

spita

l,sex,

race,and

dateofbirth,

rand

omlypicked

from

birthregiste

r(∗

)

Yes,grou

pscomparable

andalso

adjuste

dfor

mostp

otentia

lconfou

nders(∗∗

)

Yes,teleph

onic

interviewin

cases

andcontrols(∗)

Yes(∗

)Described,

25%loss(∗)

Goo

dqu

ality

Blaire

tal.

2009/Eng

land

[9]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,fro

mthe

maternitydatabase

ofho

spita

l(∗

)

No,grou

psno

tcomparable.Not

adjuste

dform

ost

potentialcon

foun

ders

Yes,ho

mev

isitsand

questio

nnaire

incasesa

ndqu

estio

nnaire

incontrols(∗)

No

Described,

5–14%lossin

thetwo

grou

ps(∗)

Goo

dqu

ality

Venn

emann

etal.200

9,Germany[29]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,matched

fora

ge,

gend

er,region,

and

sleep

time(∗

)

Yes,grou

pscomparable

andalso

adjuste

dfor

mostp

otentia

lconfou

nders(∗∗

)

Yes,ho

mev

isitsand

questio

nnaire

incasesa

ndcontrols

(∗)

Yes(∗

)

Described,

18–4

2%loss

inthetwo

grou

ps(∗)

Goo

dqu

ality

L’Hoire

tal.

1998,Th

eNetherla

nds

[21]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,matched

ford

ate

ofbirth(∗)

No,grou

psno

tcomparable.Not

adjuste

dform

ost

potentialcon

foun

ders

Yes,ho

mev

isitsand

questio

nnaire

incasesa

ndcontrols

(∗)

Yes(∗

)Not

describ

edGoo

dqu

ality

Broo

keetal.

1997,Scotland

[20]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,matched

fora

ge,

season

,and

maternity

unit(∗)

Yes,grou

pscomparable

andalso

adjuste

dfor

mostp

otentia

lconfou

nders(∗∗

)

Yes,ho

mev

isitsand

questio

nnaire

incasesa

ndcontrols

(∗)

Yes(∗

)Described,

∼25%loss(∗)Goo

dqu

ality

Flem

ing1996,

England

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,infantsb

orn

immediatelybefore

andaft

ertheind

excase

(∗)

Yes,grou

pscomparable

andalso

adjuste

dfor

mostp

otentia

lconfou

nders(∗∗

)

Yes,ho

mev

isitsand

questio

nnaire

incasesa

ndcontrols

(∗)

Yes(∗

)Described,

∼9%

loss(∗)

Goo

dqu

ality

Williamse

tal.

2002,N

ewZe

aland[24]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,rand

omly

selected

from

all

births,excepth

ome

births

(∗)

No,grou

psno

tcomparablea

ndalso

adjuste

dform

ost

potentialcon

foun

ders

(∗)

Yes,interviewbased

incasesa

ndcontrols

(∗)

Yes(∗

)Described,

10–19%

loss

(∗)

Goo

dqu

ality

Ball2003,

United

Kingdo

m[12]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,healthyinfants

andmothers,

delivered

at36+

weeks.Followed

uptill4

mon

thso

fage

(∗)

Yes,grou

pscomparable.Not

adjuste

dform

ost

potentialcon

foun

ders

(∗)

Yes,sle

eplogs

were

used

tomeasure

the

expo

sure

status

(∗)

Yes(∗

)Described,

∼40

%loss(∗)Goo

dqu

ality


Table3:Con

tinued.

Stud

yauthor,

year,cou

ntry

Selection

Com

parabilityof

cases

andcontrolson

the

basis

ofthed

esignor

analysis

Expo

sure

Com

ment

Isthec

ase

defin

ition

adequate?

Representativ

eness

ofthec

ases

Selectionof

controls

Definitio

nof

controls

Ascertainm

ento

fexpo

sure

Thes

ame

metho

dof

ascertain-

mento

fcases

andcontrols

Non

respon

serate

McC

oyetal.

2004,U

SA[14

]Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,follo

wup

ofinfantsb

ornat

selected

study

hospita

ls(∗)

Yes,grou

pscomparable

andalso

adjuste

dfor

mostp

otentia

lconfou

nders(∗∗

)

Yes,mailed

questio

nnaire

(∗)

Yes(∗

)Described,

∼30%loss(∗)Goo

dqu

ality

Lahr

etal.

2007,

USA

[15]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,str

atified

sample

draw

neach

mon

thfro

mrecentlyfiled

birthcertificates

(∗)

Yes,grou

pscomparable.Not

adjuste

dform

ost

potentialcon

foun

ders

(∗)

Question

naire

based

(∗)

Yes(∗

)Described,

26.5%loss(∗)Goo

dqu

ality

Tan2011,

Malaysia

[17]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,controls

attend

inghealth

facility(∗)

Yes,infantsu

pto

6mon

thsa

ttend

ing

health

clinics

(∗)

Yes,grou

pscomparable

andalso

adjuste

dfor

mostp

otentia

lconfou

nders(∗∗

)

Face-to

-face

interviewsu

singa

pretestedstr

uctured

questio

nnaire

(∗)

Yes(∗

)Described,

<5%

loss(∗)

Goo

dqu

ality

Mollborgetal.

2011,Sweden

[18]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,rand

omly

selected

families

with

infantsw

hohad

reached6mon

thso

fage

(∗)

Yes,grou

pscomparable

andalso

adjuste

dfor

mostp

otentia

lconfou

nders(∗∗

)

Yes,mailed

questio

nnaire

(∗)

Yes(∗

)Described,

31.5%loss(∗)

Goo

dqu

ality

Flicketal.

2001,U

SA[11]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,pregnant

wom

enenrolledat28

wk,

contactedatarou

nd8

weeks

after

delivery

(∗)

Yes,grou

pscomparable.Not

adjuste

dform

ost

potentialcon

foun

ders

(∗)

Yes,mailed

questio

nnaire

(∗)

Yes(∗

)Described,

2.2%

loss(∗)

Goo

dqu

ality

Blaira

ndBa

ll2004,U

nited

Kingdo

m[13]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,healthynewbo

rninfantsa

ndmothers

atho

me(∗

)

Yes,grou

pscomparable.Not

adjuste

dform

ost

potentialcon

foun

ders

(∗)

Yes,sle

eplogs

and

interviews(∗

)Yes(∗

)Described,

<20%loss(∗)Goo

dqu

ality

Blaire

tal.

2010,U

nited

Kingdo

m[16]

Yes,record

valid

ation(∗)

Yes,obviou

slyrepresentativ

eserie

sofcases

(∗)

Yes,commun

itycontrols(∗)

Yes,infantso

fall

pregnant

women

resid

ingin

the3

health

distric

tsof

Avon

;age

grou

p:birthto

4years

(∗)

Yes,grou

pscomparable.Not

adjuste

dform

ost

potentialcon

foun

ders

(∗)

Yes,mailed

questio

nnaire

(∗)

Yes(∗

)Described,

∼50%loss(∗)Goo

dqu

ality

∗

One

point,∗∗

twopo

ints.


Blair and Ball 2004

Study

McCoy et al. 2004

ID

3.09 (2.67, 3.58)

6.60 (3.29, 14.70)

3.00 (2.60, 3.50)

ES (95% CI)

100.00

3.79

96.21

Weight (%)

0.068 1 14.7

Overall (I2 = 75.6%, P = 0.043)

Figure 2: Forest plot: bed share and breastfeeding.

Heterogeneity between groups

Last night

ID

Vennemann et al. 2009Carpenter et al. 2004

McGarvey et al. 2006

Blair et al. 2009

Bubnaitiene et al. 2005

Blair et al. 1999

Ruys et al. 2007

Williams et al. 2002

Study

Routine

L’Hoir et al. 1998Klonoff-Cohen and Edelstein 1995

Brooke et al. 1997

Fu et al. 2010

Arnestad et al. 2001

2.36 (1.97, 2.83)

ES (95% CI)

2.51 (1.95, 3.23)

2.71 (1.44, 5.10)1.56 (0.91, 2.68)

3.53 (1.40, 8.93)

2.52 (1.19, 5.42)

0.09 (0.01, 1.60)

9.78 (4.02, 23.80)

2.73 (1.34, 5.55)

2.62 (1.93, 3.53)2.22 (1.71, 2.87)

1.78 (0.47, 6.43)1.21 (0.59, 2.48)

2.90 (0.75, 11.30)

2.00 (1.20, 3.40)

1.66 (0.57, 4.85)

100.00

Weight (%)

51.18

8.1211.13

3.78

5.65

0.42

4.10

6.43

35.6148.82

1.906.30

1.76

11.97

2.83

0.006 1 167

(P= 0.499)

Subtotal (I2 = 47.4%, P = 0.091)

Subtotal (I2 = 55.0%, P = 0.038)

Overall (I2 = 48.5%, P = 0.025)

Figure 3: Forest plot: bed share and SIDS.

3.09; 95% CI (2.67, 3.58); 𝐼2 = 75.6%; Figure 2). Since all wereobservational studies, the quality of evidence as assessed byGRADE criteria was found to be low (Table 4).

3.2. SIDS. All except one study that evaluated the associationbetween bed sharing and SIDS were from developed coun-tries [26]. The attrition rate varied from 2.2% to 50% in allbut two studies where it was unclear [21, 27].The attrition ratefor both the groupswas calculated separately by percentage ofthose who responded to the total questionnaires distributedfor each group. Five studies reported routine or usual bedsharing [9, 12, 20, 26, 28], whereas; rest reported bed sharingon a particular night (last sleep for cases and referencesleep for controls).When we separately studied routine/usual

versus last/reference sleep bed sharing, we found similarincrease in risk (Figure 3). This means that pattern of bedsharing does not affect the SIDS risk. More than half of thestudies showed significant association between bed sharingand SIDS in the enrolled infants (Table 2). Pooled analysis ofall 13 studies demonstrated 2.4-fold odds of being exposed tobed share in those who die of SIDS compared to the controls(aOR 2.36; 95% CI (1.97, 2.83); 𝐼2 = 48.5%; Figure 3). Giventhat all were observational studies, the quality of evidence asassessed by GRADE criteria was found to be low (Table 4).

3.3. Secondary Outcomes. None of the included studies hadreported the incidence of hypothermia or sepsis, NMR,among the enrolled infants.


Table4:GRA

DEevidence

tablefor

assessmento

fbed

sharev

ersusn

obedsharefor

neon

ates.

Qualityassessment

Summaryof

finding

s

Participants

(studies)

Follo

wup

Risk

ofbias

Inconsistency

Indirectness

Imprecision

Publication

bias

Overall

quality

ofevidence

Stud

yeventrates

(%)

Relativ

eeffect

(95%

CI)

Anticipated

absoluteeffects

With

nobedshare

With

bedshare

Risk

with

nobedshare

Risk

difference

with

bedshare

(95%

CI)

Sudd

eninfant

deathsynd

rome(criticaloutcome,assessed

with

interviewbased)

13072

(14stu

dies)

0–2years

Serio

us1

Noserio

usinconsistency

Serio

usNoserio

usim

precision

Und

etected

⊕⊝⊝⊝VER

YLO

W1du

eto

riskof

bias,

indirectness

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4. Discussion

“Bed sharing” has been commonly used interchangeably withterms like “bedding-in” or “cosleeping.” “Bed sharing” is atopic of common interest in regard to its controversial associ-ationwith sudden infant death syndrome (SIDS) on one handand breastfeeding on the other hand.There are many reasonsthat make parents prefer bed sharing with their infants, suchas ease in breastfeeding, enjoying the time spent with theinfant, comforting the infant in case he gets fussy, and to puthim to sleep, attending the infant quickly in case of anymishap or during any illness, promoting love, affection, orbonding, and so forth [12].

Breastfeeding has been proposed to be one of the mostprominent reasons for bed sharing. But studies have founddifficulties in establishing whether successful breastfeedingleads to bed sharing or bed sharing is because of breastfeed-ing. Based on the demographic and health surveys conductedbetween years 2002 and 2008, WHO presented data onindicators assessing infant feeding practices for 46 countries[31]. The data showed that breastfeeding rates are the highestin early infancy, which is also the timewith the highest preva-lence of bed sharing. In a systematic review based on cross-sectional studies in infancy beyond the neonatal period theauthors found a positive correlation between bed sharing andbreastfeeding [32]. However, in a longitudinal study a two-way, complex, interdependent, and temporal relationship wasfound which was itself insufficient to distinguish the inde-pendent role of bed sharing in breastfeeding [16]. A commonperception is that mothers who breastfeed commonly alsobed share frequently in order to avoid any interruption inbreastfeeding at night.

The present systematic review demonstrates significantlyassociation between bed sharing during the neonatal periodand breastfeeding at 4–6 weeks of age and at 6 month of age.Admittedly, the quality of evidence was low. Although thedata generated from observational studies are of low quality,observational studies are still the most common source ofinformation available to SIDS researchers. The studies werealso heterogeneous, but we could not carry out either sub-group or metaregression analyses to investigate the cause ofheterogeneity because of the small number of studies.

The AAP task force on SIDS recommends that bedsharing should be avoided when the infant is younger than3 months irrespective of parents smoking status. They alsodescribe that breastfeeding is associatedwith a reduced risk ofSIDS, and if possible, mothers should exclusively breastfeedfor 6 months as per the recommendations of the AAP [33].These statements are perplexing andmight be difficult for theparents to follow.

4.1. Comparison with the Existing Literature. A recently donemeta-analysis on relationship between bed sharing and SIDSincluded case-control studies with predefined criteria (anadequate definition for SIDS; autopsies performed in >95%of cases; an appropriate description of SIDS ascertainmentin the study population; a clear description of the processof control selection; and sufficient data to calculate ORs and95% CIs or the actual ORs and 95% CIs were provided) [34].

The combined OR for SIDS in all bed share versus nonbedshare infants was 2.89 (95% CI 1.99, 4.18). The risk was thehighest when maternal smoking was present (OR, 6.27 (95%CI 3.94, 9.99)), and the infant was <12 weeks old (OR, 10.37(95% CI 4.44, 24.21)). In this meta-analysis bed sharing asan exposure was studied at any time period during infancyand included both routine as well as last night bed share.In contrast, we studied bed sharing as an exposure startingduring the neonatal period and continued thereafter for avariable time period. Besides this, we also studied breast-feeding simultaneously whichwas not done in the abovemen-tioned meta-analysis.

The included studies in presentmeta-analysis consistentlyaimed to identify the prevalence of known or potential riskfactors for SIDS. Three studies more specifically aimed toinvestigated bed sharing and SIDS [19, 27, 28]. One study [30]reported bed sharing including those sleeping on themattressas well as sofa, while another studied bed sharing duringthe daytime also (this was not used in the present review)[19]. Definitions of sleeping location, whether bed sharingor nonbed sharing, were heterogeneous. For the outcome ofSIDS, the most frequently investigated interaction with bedsharing was smoking (most commonly by the mother eitherduring pregnancy or postpartum).We reported the outcomesafter adjusting for smoking. An important point that needsmentioned here is that none of the studies reviewed distin-guish between planned and accidental bed sharing, a featurethat is probably one of the biggest factors involved in thestudies identifying an increased risk of this practice.

Only one study from developing country was included inthe presentmeta-analysis [26].This study reported rate of bedsharing to be 14% in the control subjects, while the SIDS ratein the country was low (0.3 per 1000 live births). Asian coun-tries like Japan and China, though developed, have a lowerrate of SIDSdespite a higher rate of bed sharing [35, 36]. A bedsharing rate of 37% was reported in Japan in year 2006 whenthe rate of SIDSwas only 0.16 per 1000 live births, and the cor-responding figures in China were 24% and 0.16, respectively,during year 2002. Considering these figures, a general rec-ommendation of restricted bed sharing might not be appro-priate for developing (including Asian) countries in contrastto developed countries where other known risk factors mightplay important role.

Published studies from developing countries and partic-ularly fromAsian community show a low rate of SIDS in spiteof a higher rate of bed sharing.This lower prevalence of SIDSis whether due to the protective effect of breastfeeding or isjust a reflection of the demographic that chooses breastfeed-ing is a matter of debate. One study supported these findingsand showed that exclusive breastfeeding at 1 month of agehalved the risk, and even partial breastfeeding at 1 month ofage reduced the risk [37]. They also found a high incidenceof SIDS below 6 months age, and based on these findingsthey recommended that breastfeeding should be continueduntil at least 6 months of age when the risk of SIDS dimin-ishes. A recent meta-analysis including 18 studies showedthat breastfeeding is protective against SIDS, and this effect isstronger when breastfeeding is exclusive [38]. While both thestudies identified a direct protective effect of breastfeeding on


SIDS, neither of them examined the impact of bed sharing onthe individual outcomes. But studies examining the risk fac-tors for SIDS have found the risk of bed sharing to be so pro-found that the protective effect of breastfeeding did not sig-nificantly influence the magnitude of the risk associated withbed sharing [39–41]. This has been hypothesized to be due tothe lifestyle and socioeconomic class that decides both breast-feeding and SIDS rates supported by findings from developedversus developing or Asian countries [40, 42]. Finally, it isactually difficult to isolate breastfeeding and bed sharing fromother risk factors related to SIDS.

We did not find any relevant studies, with a contem-poraneous comparison, examining the effect of bed sharingin relation to other outcomes of interest (the incidence/prevalence of hypothermia, mortality, and sepsis rate in bedsharing neonates or infants).

4.2. Strengths and Weaknesses of Review. The strength ofpresent systematic review is that it included studies havingexposure to bed share during neonatal period (and continuedthereafter) and addressed both the benefits (breastfeeding)and risks (of SIDS) of bed sharing. But there are somepotential limitations that merit attention: (a) methodologicalissues: all the studies were observational and were conductedmostly in developed country settings; the age group includedfrom the neonatal period and up to 2 years of age, thusmaking it difficult to generalize the result (as SIDS is meantfor during infancy only); the control groups were alsovariably defined in all the studies (as shown in Table 2); (b)dramatic change in SIDS epidemiology during the last decade[43]; (c) since we included only studies having exposureto bed share during neonatal period and excluded thosehaving exposure during last sleep only, our results cannotbe generalized to SIDS as a whole in infancy, as last nightbed sharing that happened after the neonatal period hasnot been captured in our review. Also, we were not able toevaluate the “net” beneficial effect of the intervention as noneof the studies had reported both breastfeeding and SIDS ratestogether.

4.3. Further Area of Research. A total of 21 observationalstudies (breastfeeding and bed sharing = 8; SIDS and bedsharing = 13) were included in the present review. None ofthe studies reported both the primary outcomes (SIDS andbreastfeeding) in bed sharing population, so we were notable to evaluate the “net” effect of bed sharing. Most of theincluded studies were undertaken more than a decade ago,and the prevalence of bed sharing might have changed asa result of guideline recommendations or societal factors.Bed sharing is a well-known cultural practice in developingcountries, but only one study was found to be eligible forinclusion in the review. Control groups were also variablydefined in all the included studies. Because prospectivestudies of SIDS are not possible given the now rarity of thesedeaths, more detailed retrospective studies that look at bedsharing, breastfeeding, and the hazardous circumstances thatput babies at risk are needed.

5. Conclusion

There is low quality evidence that bed sharing is associatedwith higher breastfeeding rates at 4 weeks of age andincreased risk of SIDS irrespective of maternal smoking. Dueto paucity of studies, it is difficult to predict whether neonatesare at a more risk than older infants (>1 month age). We needmore detailed studies that look at bed sharing, breastfeedingand hazardous circumstance that put babies at risk.

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper.

Acknowledgments

WorldHealthOrganization (WHO) provided funding for theconduction of systematic reviews so as to formulate certainguidelines and to make policy on issues related to newbornhealth. As a part of this incentive, a systematic review wasconducted on the safety and efficacy of “bed share” during theneonatal period.The funder had no role in study design, datacollection and analysis, decision to publish, or preparation ofthe paper.

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