ORIGINAL ARTICLE

Sudden unexpected death in infancy (SUDI) in the early neonatalperiod: the role of bed-sharing

Charlotte Hoffend • Jan-Peter Sperhake

Accepted: 3 December 2013

� Springer Science+Business Media New York 2014

Abstract The incidence of sudden infant death syndrome

(SIDS) has declined substantially, but the proportion of sud-

den unexpected death in infancy (SUDI) in neonates,\7 days

old, has increased among all SUDI cases in the first year of

life. The aim of this study was to analyze circumstances and

common features of SUDI cases during the first 7 days of life.

Data have been gathered retrospectively from Departments of

Legal Medicine in Germany and Austria by using a stan-

dardized questionnaire. 19 out of 46 children died within 24 h

after birth. A possible reason for this could be a lack of

awareness of the needs of the newborn on the part of an

exhausted mother. Fifty-two percent of the incidents occurred

while the mother and her newborn were still hospitalized in a

birth clinic. Forty-eight percent of the infants had been

sleeping in the parents’ bed with mother and/or father. In

11 % of the cases, there was a sofa-sharing situation. Bed-

sharing seems to increase the risk for SIDS in the newborn

period as well as the risk for accidental suffocation/asphyxia

of the baby. Therefore, mothers should not be instructed to

bed-share. Particularly during the first 24 h after birth, it may

be advisable to check mothers and infants regularly.

Keywords Bed-sharing � SIDS � SUDI � Newborn

period � Breastfeeding

Introduction

Little is known about sudden infant death syndrome (SIDS) in

the newborn period. The most recent definition of SIDS is the

so-called San Diego Definition, which is a consensus of a

meeting in San Diego, USA, in 2004 [1]: SIDS is defined as the

sudden unexpected death of an infant \1 year of age, with

onset of the fatal episode apparently occurring during sleep,

that remains unexplained after a thorough investigation,

including performance of a complete autopsy and review of

the circumstances of death and the clinical history. According

to this definition, a category IA SIDS infant, a ‘‘typical’’ SIDS

infant, is referred to as an infant older than 21 days and

younger than 9 months.

The incidence of SIDS in Germany declined substantially

in the mid-1990s, as it did in many other countries, due to

international and regional back-to-sleep campaigns dis-

couraging parents from letting their infants sleep in the prone

position. The drop in the German SIDS rate continues [2], but

the proportion of sudden unexpected death in infancy (SUDI)

in newborns\7 days old, among all SUDI cases in the first

year of life, has been increasing substantially from only 5 %

in the early 1990s to 20 % in 2011, although the total num-

bers of cases per year remained relatively stable (Fig. 1).

Newborn infants do not seem to benefit from SIDS preven-

tion campaigns to the same extent as older infants. However,

SUDI in the newborn period is only rarely targeted by sci-

entific studies. In some case–control studies, the newborn

status is even an exclusion criterion [3].

The aim of this study was to analyze circumstances and

common features of SUDI cases during the first 7 days of

life, with special regard to bed-sharing.

Materials and methods

Data about SUDI cases in the first 7 days of life was

gathered retrospectively. Only cases which could not be

explained by defined internal diseases or complications of

C. Hoffend � J.-P. Sperhake (&)

Department of Legal Medicine, University Medical Center

Hamburg-Eppendorf, Butenfeld 34, 22529 Hamburg, Germany

e-mail: sperhake@uke.de

123

Forensic Sci Med Pathol

DOI 10.1007/s12024-013-9518-3

prematurity were included. Departments of Legal Medicine

in Germany, Austria, and Switzerland were asked to fill out

a questionnaire based on autopsy reports and criminal files

in which anonymized case details could be provided. Cases

occurring between January 1996 and June 2011 were

included. Preliminary surviving post-resuscitation cases

were also included, when the incident took place within the

first 7 days of life.

With respect to the design of the questionnaire it was

important to make sure that the questions were com-

prehensible and non-ambiguous. Most of the questions

were multiple choice. The questions mainly referred to

infants’ sleeping position, whether children and parents

were sleeping in the same bed, and the detailed cir-

cumstance of death such as time of day or date

(Table 1). It was possible to document further informa-

tion or details like APGAR-score, conspicuous autopsy

results, drug abuse, etc. in a non-standardized manner, at

the end of the questionnaire.

A database was produced from these questionnaires

using Epi InfoTM 6 which is provided by the World Health

Organization. Epi InfoTM 6 is a series of microcomputer

programs for handling epidemiologic data in questionnaire

format and for organizing study designs and results into

text that may form part of written reports. It allows various

epidemiologic data management and analysis techniques.

Results

36 departments of Legal Medicine in Germany, Austria,

and Switzerland were asked for cases meeting the inclusion

criteria. 27 departments participated in the survey. Data

from 46 cases (sex ratio f:m = 1.05:1.00) from Germany

and Austria (none from Switzerland) were obtained.

53 % of the incidents occurred within a hospital (16 %

in the baby’s room of the birth clinic, 33 % in the mother’s

room, and 4 % in a pediatric clinic) with a mean age of

1.7 days. 40 % of the deaths occurred at home (20 % in the

parents’ bedroom, 2 % in the baby’s room, and 18 % at

home with the room unknown) with a mean age of 4.5 days

(Fig. 2). 22 (48 %) of the newborns had been sleeping in

the parents’ bed with their mother and/or father, 11 (24 %)

in a cot, two in a bedside crib, and five incidents (11 %)

occurred on a sofa with the mother (Fig. 3).

Figure 4 shows the age distribution of the cases with a

peak on day 1 and a relatively consistent distribution of all

other cases on days 2–7. 72 % of deaths occurred between

12 and 9 a.m. 58 % died within the 6 h between 3 and

9 a.m.

Table 1 Items in the questionnaire

Time of recovery Date, time

Last seen alive? Date, time

Basic epidemiological data Age, gender, birth weight, birth length

Pregnancy and birth

related data

Duration of pregnancy, location of

delivery, birth mode

Breast feeding Yes/no? Breastfeeding when last seen

alive?

Age of mother Years

Is the mother smoking Yes/no?

Locality of the incident Birth clinic (Baby’s/Mother’s room),

Children’s hospital, at home (parents’

bedroom, baby’s room)

Bed circumstances Parents’ bed (alone/with parents), crib,

bedside crib, etc.

Bedding Mother’s blanket, Baby’s blanket,

sleeping bag

Was the face covered? Yes/no?, which covering

Position in which the

infant was found dead

Prone/supine/side

Resuscitation? Yes/no? If yes, temporarily surviving?

Autopsy? Yes/no?

It was possible to add free comments. Missing items were labeled as

‘‘unknown’’

Fig. 2 Place of deathFig. 1 Number (columns) and proportion of neonates (\7 days old)

among all SUDI cases during the first year of life (curve) in Germany

1980–2011, according to Germany’s Information System of the

Federal Health Monitoring (until 1998 ICD9 Codes 797-799, from

1998 on ICD10 codes R95-R99 [5])

Forensic Sci Med Pathol

123

The birth mode was known in 32 cases (86 %). 23 cases

(50 %) were straightforward vaginal deliveries, in five

cases the vaginal deliveries were accompanied by com-

plications, and in 4 cases, the birth was via a cesarean

section. The mean birth weight was 3,159 g (±558 g). The

mean birth length was 50.9 cm (±2.3 cm). The mean

duration of the pregnancy was 39 weeks. The mean age of

the mother was 30.0 (±7.9) years. As far as the sequence in

birth order was known (65.2 %), 60 % of the mothers were

primipara.

27 children were breast fed and four were bottle fed. In

15 cases, there was no information about feeding habits.

The last living contact for 15 of the breastfed children had

been during a nursing situation, whereas 11 of these chil-

dren died while sharing a bed with one of the parents.

In 37 cases (80 %) cardio-pulmonary resuscitation was

attempted, three of which were primarily successful with a

0–19 days survival rate. There were no significant findings

from toxicological analysis in any of the cases (apart from the

finding of resuscitation-related drugs in some cases). Data on

the smoking habits of the mother, alcohol or drug use, the

number of people in the household, siblings, bedding items,

or of the infant’s position when they were found dead, was

only sparsely available and therefore has not been evaluated.

Siblings were not involved in any of the cases.

Discussion

The circumstances of death and epidemiologic factors of

46 cases of early SUDI in Germany and Austria were

investigated. SUDI in the early neonatal period, occasion-

ally referred to as SUEND (Sudden Unexpected Early

Neonatal Death) [4], account for a significant part of all

SUDI. The incidence of SUDI in infants younger than

7 days with ICD10 codes R95-99 was 0.072 of 1,000 live

born infants in 2011 [5]. According to Germany’s Infor-

mation System of Federal Health Monitoring, 1,040 infants

younger than 7 days died from causes labeled with the

ICD10 codes R95-R99 (ICD9 798-799 prior to 1998)

between 1996 and 2009, therefore comprising nearly all

SUDI cases or other ill-defined causes of death in the early

newborn period. In Germany, only cases where the pros-

ecution finds it necessary to exclude a third party fault

undergo a legal autopsy. In order to get to a prosecutor’s

attention, certification of a non-natural death by the

physician who does the external examination of the body is

a prerequisite. As a result, a selection bias in the presented

subset of cases cannot be excluded.

Another limitation of the present study is the retro-

spective collection of data. Whereas the recording of

autopsy findings is largely standardized in the German

speaking countries, this is not the case for all aspects of the

circumstances of death documented by the police. In many

cases, the exact situation, for example, the infant’s position

or if they were covered by blankets, cannot be recalled by

the person recovering the death (in most cases the mother).

However, these shortcomings result in an unsatisfyingly

large proportion of missing data with regard to the actual

death scene and other important issues, such as the pre-

sence or absence of known risk factors for SIDS including

smoking habits, sleeping position, etc. As a result, this

retrospectively obtained data set should be regarded as a

pilot study which points to a specific problem and might

raise more questions than it answers.

In the present study, 19 out of 46 children (41 %) died

on day one, even though their delivery was uncomplicated

and the newborn was in good health immediately after

birth. Grylack et al. [6] reported on apparent life threat-

ening events (ALTE) in 20 newborns, 10 of which

occurred on day one. One possible reason for this could

be the lack of alertness on the part of the exhausted

mother for the needs of the newborn. Dageville [7]

demands that mothers and children should be monitored

in the first hours after giving birth. Particularly, the

combination of primipara, skin-to-skin contact, and leav-

ing mother and child on their own after the birth, poses a

high risk. Poets et al. [8] point to the potential hazard of

accidentally covering the baby’s mouth and nostrils,

especially if the newborn is lying on its mother’s stomach

Fig. 3 Bed situation when baby was found dead

Fig. 4 Age distribution

Forensic Sci Med Pathol

123

or on her breast. Thus, the authors suggest that super-

vising mother and child in short intervals might be

advisable in certain situations (especially if the mother is

inexperienced). In the present study, 60 % of mothers

were primipara. A correlation with the birth method could

not be demonstrated. In the present study, the delivery had

been via a cesarian section in 4 cases, which is a ratio of

12.5 %. In the normal population, the percentage of

cesarian sections in German hospitals was 32 % in 2010

[9]. These findings could support the hypothesis that pri-

miparous mothers, who, on the average, experience longer

durations of vaginal deliveries and therefore tend to be

more exhausted, pose a risk to the newborn. On the other

hand, a cesarian section could protect the infant from

SUDI, because the mother gets more professional atten-

tion after anesthesia and is likely to be less exhausted and

therefore more attentive to the baby. To what extent drugs

were applied before or during delivery could not be

clarified in this study. The application of systemic anal-

gesics before or during the delivery is atypical. In vaginal

deliveries, analgesia is generally done by peridural anes-

thesia, and by spinal anesthesia in cesarian sections

respectively. Both of these methods do not sedate the

mother, but this is not entirely true for the baby. These

drugs can enter the maternal circulation and also cross the

placenta, which can have an adverse effect on the baby.

Some of the deaths might be explained by these effects.

Therefore it may be advisable to measure drug levels in

newborns, particularly in cases in which death occurs on

day one.

In the present study, the vast majority of fatalities

occurred during the second half of the night. In various

published case samples ALTE as well as SUDI occurred

during the second half of the night and the early morning

hours [10, 11]. This might be associated with the fact that

mothers and children in delivery wards are infrequently

monitored during the night and hazardous situations are not

noticed early enough.

There seems to be a strong predominance of bed-

sharing and sofa-sharing situations in early SUDI cases.

Almost half of the infants (48 %) had been bed-sharing

when they died. In a further five cases (11 %) there was

a sofa-sharing situation. Our results are in accordance

with the results of a case control study by Tappin [12]

who demonstrated that bed-sharing increases the risk of

SIDS for children \11 weeks of age [Odds ratio (OR)

10.2]. In a meta-analysis of eleven studies, Vennemann

et al. [13] were able to show a tenfold increased risk for

children \12 weeks old in a bed-sharing situation. This

might be explained by the higher risk of the baby’s head

getting covered by the parent’s duvet, overheating in

close contact to the parents, or accidental covering of the

mouth and nostrils. Ruys et al. [14] showed that even

after correcting for parental smoking, the odds ratio for

cot death during bed-sharing with parents is 9.1 at

1 month. The risk decreases continuously as the infant

gets older with an OR of 1.3 for 4 month old babies

[14]. Parental consumption of alcohol seems to addi-

tionally increase the risk [15, 16]. In an analysis of five

case–control-studies in 2013, Carpenter et al. [17] cal-

culated a fivefold increased risk for SIDS in infants

younger than 3 months who shared the bed with a par-

ent, even if the infants were breast-fed, both parents

were non-smokers, and the mother consumed neither

alcohol nor drugs. The authors recommend avoiding bed-

sharing in early infancy in order to decrease SIDS rates.

One might argue that if sofa-sharing is eliminated from

the case sample, less than half of the remaining cases are

associated with bed-sharing. Sofa-sharing certainly implies

specific risk factors as opposed to ‘‘mere’’ bed-sharing, but

the sharp discrimination between sofa-sharing in bed-

sharing might be artificial to some extent. There may be

many common features shared by sofa-sharing and bed-

sharing situations that altogether comprise the increased

risk. To some extent the risk of both sleeping arrangements

could result chiefly of the close proximity between a baby

and an adult. The main difference might be the upholstered

back rest of the sofa, which might cause oppression to the

infant. However, even if the sofa-sharing cases are left

aside, bed-sharing seems to be over-represented with 48 %

of the cases in this study. In a meta-analysis, Vennemann

et al. [13] found 13.3 % of bed-sharing in controls and

28.8 % in SIDS-cases in the first year of life. Unfortu-

nately, figures on the prevalence of bed-sharing in the first

week of life are not yet available and should be a target of

future research.

In 15 cases of the present study, the mother fell asleep

while breast feeding. Probably a tired mother nursing her

child and falling asleep during breast feeding constitutes a

particular hazard for the newborn. In some cases, a possible

mechanism of death might be asphyxia due to soft cover-

ing. However, there was not enough information available

on whether the infant’s face was still covered by the

mother’s breasts when found dead.

More than half of the reported deaths occurred in clin-

ical surroundings, most of them in birth clinics. This

illustrates the alarming fact that even hospitals, where, in

principle, children are monitored, cannot protect healthy

infants from early SIDS; this is not only dramatic for the

affected families but also for the hospitals involved. Also,

infants beyond the neonatal period are obviously not safe

from life threatening episodes or even death when attended

in child care settings. De Jonge [18] showed that based on

the hours usually spent in child care, the number of infants

that died from SIDS while attending child care was 4.2

times higher than expected.

Forensic Sci Med Pathol

123

Conclusions

Sudden death in infancy (SUDI) is not only a problem of

the post-neonatal period but also of neonates. A large

proportion of such fatalities occur in bed-sharing situations

within maternity wards. Mothers should be informed of the

potential risks of bed-sharing with a newborn. Bonding and

breast feeding are of great importance for the well-being of

both, infant and mother. Breast feeding is a protective

factor against SIDS and therefore should be promoted, but

mothers have to be educated and informed not to fall asleep

during the nursing of their child. The staff of maternity

wards should be trained accordingly. Especially during the

first 24 h after birth, frequent monitoring of mothers and

children at short intervals should be considered. We

encourage scientists, forensic experts, and police investi-

gators to come to a more detailed reconstruction of the

death scenes in order to further elucidate the chain of

events and to identify accidental suffocation cases. A

prospective multi-center case–control study on specific risk

factors for SUDI in the newborn period would be desirable

for future research.

Key points

1. Bed-sharing or sofa-sharing are associated with SUDI

in the early neonatal period in more than 50 % of

cases. It may not be advisable to recommend bed-

sharing during the newborn period.

2. Monitoring of mothers and their babies in the first

hours after birth may help to protect newborns from

sudden death.

3. Bonding and breastfeeding are of great importance but

falling asleep during nursing might be dangerous in the

early neonatal period, especially in inexperienced

mothers, extremely tired mothers, or mothers under

the influence of drugs.

4. The staff of maternity wards should be aware about the

potential risks of bed-sharing during the newborn

period.

5. Future studies of sudden infant death in the neonatal

period should include detailed information about

bed-sharing, as well as many issues/items that were,

unfortunately, not available in this pilot study.

6. In Germany and Austria, investigation of newborn

infant deaths should incorporate a detailed list of

important information (method of birth, pregnancy

number, medications, length of labor, breast vs

formula, etc.) so that associations can be better-

identified, and preventative strategies employed.

Acknowledgments We sincerely thank our contributing colleagues

from Germany and Austria: S. Banaschak, Universitatsklinikum Koln,

Institut fur Rechtsmedizin; V. Becker, Universitatsklinikum Magde-

burg, Institut fur Rechtsmedizin; D. Boy, Universitatsklinikum

Rostock, Institut fur Rechtsmedizin; R. Dettmeyer, Justus-Liebig-

Universitat Gießen, Institut fur Rechtsmedizin; C. Erfurt, Medizini-

sche Universitat Carl Gustav Carus an der Technischen Universitat

Dresden, Institut fur Rechtsmedizin; P. Grabuschnigg, Gerichtliche

Medizin Graz; S. Guddat, Charite Universitatsmedizin Berlin, Institut

fur Rechtsmedizin; B. Hartung, Universitatsklinikum Dusseldorf,

Institut fur Rechtsmedizin; S. Heide, Universitat Halle (Saale);

Institut fur Rechtsmedizin; T. Kamphausen, Universitatsklinikum

Essen, Institut fur Rechtsmedizin; M. Klintschar, Medizinische

Hochschule Hannover, Institut fur Rechtsmedizin; C. Konig, Uni-

versitat Leipzig, Medizinische Fakultat, Institut fur Rechtsmedizin;

H–W. Leukel, Klinikum der Johann Wolfgang Goethe- Universitat

Frankfurt, Institut fur Rechtsmedizin; B. Madea, Universitat Bonn,

Institut fur Rechtsmedizin; R. Pircher, Universitatsklinikum Freiburg,

Institut fur Rechtsmedizin; A. Sassenberg, Institut fur Rechtsmedizin

und Verkehrsmedizin im Klinikum der Universitat Heidelberg;

M. Verhoff, Justus-Liebig-Universitat Gießen, Institut fur Rechtsmedizin.

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