EClinicalMedicine 14 (2019) 59 70
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EClinicalMedicine
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eclinicalmedicine
Research Paper
Perinatal or neonatal mortality among women who intend at the onset of
labour to give birth at home compared to women of low obstetrical risk
who intend to give birth in hospital: A systematic review and metaanalyses
Eileen K. Huttona,b,*, Angela Reitsmab, Julia Simionib, Ginny Bruntonc, Karyn Kaufmanb
a
b
c
Department of Obstetrics and Gynecology, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada
Midwifery Education Program, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada
EPPI-Centre, Department of Social Science, UCL Institute of Education, University College London, United Kingdom
A R T I C L E
I N F O
Article History:
Received 14 March 2019
Received in revised form 24 May 2019
Accepted 16 July 2019
Available online 25 July 2019
Keywords:
Home childbirth
Low risk birth
Perinatal mortality
Neonatal mortality
Systematic review
A B S T R A C T
Background: More women are choosing to birth at home in well-resourced countries. Concerns persist that
out-of-hospital birth contributes to higher perinatal and neonatal mortality. This systematic review and
meta-analyses determines if risk of fetal or neonatal loss differs among low-risk women who begin labour
intending to give birth at home compared to low-risk women intending to give birth in hospital.
Methods: In April 2018 we searched five databases from 1990 onward and used R to obtain pooled estimates
of effect. We stratified by study design, study settings and parity. The primary outcome is any perinatal or
neonatal death after the onset of labour. The study protocol is peer-reviewed, published and registered
(PROSPERO No.CRD42013004046).
Findings: We identified 14 studies eligible for meta-analysis including ~500,000 intended home births.
Among nulliparous women intending a home birth in settings where midwives attending home birth are
well-integrated in health services, the odds ratio (OR) of perinatal or neonatal mortality compared to those
intending hospital birth was 1.07 (95% Confidence Interval [CI], 0.70 to 1.65); and in less integrated settings
3.17 (95% CI, 0.73 to 13.76). Among multiparous women intending a home birth in well-integrated settings,
the estimated OR compared to those intending a hospital birth was 1.08 (95% CI, 0.84 to 1.38); and in less
integrated settings was 1.58 (95% CI, 0.50 to 5.03).
Interpretation: The risk of perinatal or neonatal mortality was not different when birth was intended at home or in
hospital.
Funding: Partial funding: Association of Ontario Midwives open peer reviewed grant.
Research in Context: Evidence before this study Although there is increasing acceptance for intended home birth as
a choice for birthing women, controversy about its safety persists. The varying responses of obstetrical societies to
intended home birth provide evidence of contrasting views. A Cochrane review of randomised controlled trials
addressing this topic included one small trial and noted that in the absence of adequately sized randomised controlled trials on the topic of intended home compared to intended hospital birth, a peer reviewed protocol be
published to guide a systematic review and meta-analysis including observational studies. Reviews to date have
been limited by design or methodological issues and none has used a protocol published a priori.
Added value of this study Individual studies are underpowered to detect small but potentially important differences in rare outcomes. This study uses a published peer-reviewed protocol and is the largest and most
comprehensive meta-analysis comparing outcomes of intended home and hospital birth. We take study
design, parity and jurisdictional support for home birth into account. Our study provides much needed information to policy makers, care providers and women and families when planning for birth.
Implications of all the available evidence Women who are low risk and who intend to give birth at home do not
appear to have a different risk of fetal or neonatal loss compared to a population of similarly low risk women
intending to give birth in hospital.
© 2019 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.
(http://creativecommons.org/licenses/by-nc-nd/4.0/)
* Corresponding author at: McMaster University, 1280 Main Street West, HSC 4H24, Hamilton, Ontario L8S 4K1, Canada.
E-mail address: [email protected] (E.K. Hutton).
https://doi.org/10.1016/j.eclinm.2019.07.005
2589-5370/© 2019 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license. (http://creativecommons.org/licenses/by-nc-nd/4.0/)
60
E.K. Hutton et al. / EClinicalMedicine 14 (2019) 59 70
1. Introduction
Birth has become the most common reason for hospital admission
in well-resourced countries impacting healthcare costs [1]; however,
it is unclear if hospitalisation for birth alters neonatal outcomes for
women at low obstetrical risk. A small but growing number of
women begin labour with the intention of giving birth at home [2]
and research among this self-selected group consistently reports
reduced obstetric interventions [3,4]. There is uncertainty however,
whether this reduction in maternal interventions comes at the
expense of neonatal wellbeing. In 2015, for example, two high-profile
studies of out-of-hospital (home) birth reported contradictory findings regarding perinatal mortality and morbidity [3,4].
Acceptance of home birth as a choice for women is increasing [5],
but controversy about safety persists. Quality evidence regarding outcomes associated with place of birth for low-risk pregnancies is
urgently needed to inform parents, maternity care providers and policy makers. Because individual studies are underpowered to detect
small but potentially important differences in rare outcomes, and
randomised controlled trials are not feasible and do not contribute to
these findings, a Cochrane review on this topic urged a careful systematic review and meta-analysis of cohort studies be undertaken to evaluate outcomes of intended home birth [6]. Using our peer-reviewed,
published, registered protocol [7] (PROSPERO, http://www.crd.york.ac.
uk, No.CRD42013004046) we undertook this systematic review and
meta-analyses to determine if low-risk women who intend at the
onset of labour to give birth at home are more or less likely to experience a fetal or neonatal loss compared to a cohort of similarly low-risk
women who intend at the onset of labour to give birth in hospital.
2. Methods
Methods reported previously in our published protocol [7] were
followed and are described briefly here.
2.1. Search Strategy and Study Selection
The search included studies from 1990 onward and was completed on April 11, 2018 using Embase, Medline, AMED, CINAHL, and
the Cochrane Library. Terms either as keywords or subject headings
included: home delivery, home birth, home childbirth, and homebirth. Reference lists from review articles and all included studies
were crosschecked. Two reviewers independently selected studies
for full review if they had comparison groups of women who were at
similarly low-risk for birth complications, as defined in the study
under review, and who were intending either to give birth in hospital
or home; cohorts were defined by the intended location of birth
rather than the actual location of birth; intention for a home birth
was determined or reconfirmed at the onset of labour; parity was
accounted for; and the study accounted for missing cases.
2.2. Data Collection
Two reviewers independently collected data from the included
studies using a detailed data abstraction form, compared their findings and reached consensus. Missing information was requested
from authors of included studies as necessary. Whenever possible,
findings were reported by parity sub-groups.
Because they answer somewhat different questions, we categorised
studies into one of two study designs to reflect the assembly of birth
cohorts. In all cases the comparison group included women intending
hospital birth and deemed to be at low obstetrical risk. Studies
designed to determine the safety of home birth in actual practice,
included all intended home births in a given time frame, regardless of
whether they would be considered eligible for home birth according to
local standards. These ‘pragmatic’ design studies answer the research
question: “Do women who intend at the onset of labour to give birth at
home experience a higher or lower incidence of fetal or neonatal loss
compared to women at low obstetric risk who intend at the onset of
labour to give birth in hospital?” Other studies focused on outcomes of
place of birth among women who met local selection standards for
home birth thus assuring that only those of low obstetrical risk were
included and answer the question: “Do women who intend to give
birth at home and who meet their local eligibility criteria for home
birth at the onset of labour experience a higher or lower incidence of
fetal or neonatal loss compared to women who would have been eligible for home birth but intend at the onset of labour to give birth in hospital?” The latter study design may have resulted in the exclusion of,
for example, any twin births or breech births that may have been
intended and occurred at home, but that were not supported by local
standards. We termed studies of this design ‘within standards.’ We
stratified all analyses by study design in order to address both research
questions. In addition, in order not to compromise power to find small
differences, we conducted sensitivity analyses for all outcomes without
stratification as described in the Sensitivity Analyses section below.
We hypothesised a priori [7] that the degree of support for home
birth and home birth care providers within the health care system where
the study was carried out would act as an effect modifier of the relationship between intended place of birth and birth outcomes [8]. We termed
this context for home birth, described in detail elsewhere, as a ‘well-integrated’ versus ‘less well-integrated’ home birth environment [9]. A wellintegrated setting was described as a place where home birth practitioners: are recognised by statute within their jurisdiction; have received
formal training; can provide or arrange care in hospital; have access to a
well-established emergency transport system; and carry emergency
equipment and supplies. Less well-integrated settings were those where
one or more of these criteria are absent. Studies were categorised by an
independent team of researchers [9] based on information found within
the study, from the study’s author via a questionnaire [9] about the context of care at the time their study was undertaken, and from secondary
publications such as policies or statements regarding home birth in the
country where the study took place (Table 1).
2.3. Outcome
Our primary outcome is any perinatal or neonatal death after the
onset of labour. If a study reported these data both including and
excluding malformed infants, to minimise categorisation bias we used
data that included malformations in the primary analyses. Secondary
outcomes include perinatal morality (defined as stillbirth after the
onset of labour or death to 7 completed days) and neonatal mortality
(defined as death between 0 and 28 days of a live born baby). Where
possible, we report perinatal mortality and neonatal mortality separately; and mortality rate excluding malformed infants. Additional
neonatal outcomes included neonatal resuscitation, Apgar scores of
less than 7 at 1 min and less than 7 at 5 min, and admission to a neonatal intensive care unit (NICU). Definitions used by the authors for neonatal resuscitation and NICU admissions were recorded.
Because free standing birth centres cannot be considered to be a
home or hospital setting, data from these out of hospital birth centres
were not included. For studies that had more than one hospital comparison group, outcomes for the hospital groups were combined, provided that women in the groups being combined met eligibility
criteria. If data for some or all outcomes could not be combined, we
chose the comparison group most likely to minimise confounders;
where the women were most like women choosing home birth, and
the care providers were most like those providing care at home.
2.4. Risk of Bias
Our study eligibility criteria ensured that the observational studies
included in the review had a control group, used an intention-to-treat
E.K. Hutton et al. / EClinicalMedicine 14 (2019) 59 70
61
Table 1
Studies eligible for systematic review of perinatal and neonatal outcomes, stratified by degree of integration of home birth within the health care system and by study design.
Type of integration into health system
Well-integrated
Study design
Pragmatic
(includes all women who intend home birth at onset of labour)
Within standards
(includes only women who meet criteria for birth at home at ibset )
approach (analysed by intended place of birth at the onset of labour),
and controlled for parity. Study quality was assessed using The Newcastle Ottawa Quality Assessment Scale for Cohort Studies (NOS) [10]. Risk
of publication bias across studies was assessed through inspection of
inverted funnel plots for the primary outcome [11].
Halfdandottir [27]
Hutton [28]
Hutton [3]
Janssen [21]
Janssen [22]
van der Kooy [29]
van der Kooy [19]
Wiegers [24]
Brocklehurst [23]
Davis [20]
de Jonge [25]
Hermus [26]
Pang [18]
Less well-integrated
Blix [30]
Lindgren [31]
Hiraizumi [32]
Homer [33]
2.5. Synthesis of results
Meta-analyses were conducted using the ‘metafor’ package in R
statistical software version 3.3.1. Log odds ratios (OR) and corresponding sampling variances for each study were calculated using
Fig. 1. Flow diagram of study selection.
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E.K. Hutton et al. / EClinicalMedicine 14 (2019) 59 70
Table 2
Description of included studies.
Study
Data source & time period
Method of
accounting
for parity
Methods
Nos
quality
score
Sample size
Setting and
degree of
integration
Outcomes
reported
Author
questionnaire
completed
Blix E, et al. [30]
Home: Midwife’s register, telephone
interview, and midwife’s birth protocols
Hospital:
Medical birth registry of Norway (MBRN)
1990 2007
Home: All NHS Trusts that provide
home birth services
OU: Random sample of 36 obstetric
units within the NHS
ALU: All NHS hospitals that have an
alongside unit
Data collection forms designed for this
study
2008 2010
Stratified
6
Pragmatic
Retrospective
cohort study
1631 home
16,310 hospital
Norway
(Midwives less
well-integrated)
1, 3 5, 8, 11, 12,
15 18
Yes
16,840 home
16,710 ALU
19,706 OU
11,282 FSU
Combined ALU
and OU for
comparison
group
England
(Midwives
well-integrated)
1, 2, 4, 8, 9, 11, 12,
14 18
Yes
Bolten N, et al.
[14]
DELIVER Study, recruited from 20
midwifery practices
2009 2011
Stratified
6
2050 home
1445 hospital
Netherlands
(Midwives
well-integrated)
11, 12, 14, 16 18
No infant outcomes
Yes
Davis D, et al.
[20]
Midwifery Maternity Provider
Organisation Database
2006 2007
Adjusted
8
Within
standards
Prospective
cohort study
4 groups:
Obstetric Unit,
Alongside
Midwifery Unit,
Free-standing
birth centre,
Home
Within
standards
Prospective
cohort study
Within
standards
Retrospective
cohort study
New Zealand
(Midwives
well-integrated)
8, 9, 11, 14, 16, 18
No
Stratified
8
Within
standards
Prospective
cohort study
1830 home
Primary unit
2877
Secondary
hospital
7380
Tertiary hospital
4123
Used primary
unit comparison
group
92,333 home
54,419 hospital
Netherlands
(Midwives
well-integrated)
11
No infant outcomes
Yes
Stratified
7
Within
standards
Retrospective
cohort study
Pragmatic +
Within
standards
Retrospective
cohort study
Within
standards
Prospective
cohort study
466,112 home
276,958
hospital
2000 2009
307 home
921 hospital
Netherlands
(Midwives
well-integrated)
1,2,4,5,8,9
Yes
Iceland
(Midwives
well-integrated)
1,3,4,6,8 11,14 18
Yes
1086 home
701 hospital
Netherlands
(Midwives
well-integrated)
1, 3, 4, 9 12, 14 18
Yes
Birthplace in
England
Collaborative
Group, [23]
de Jonge A, et al. LEMMoN Study database, National
[15]
Perinatal database I, National Perinatal
database II,
National Neonatal Register
2004 2006
de Jonge A, et al. National Perinatal database I, National
[25]
Perinatal database II,
National Neonatal Register
2000 2009
Halfdansdottir
Icelandic electronic birth registry and
B, et al. [27]
original midwife and doctor records
extracted by study author using a
structured item list.
2005 2009
Hermus M, et al. Midwifery practices using case report
[26]
form developed for the study and
linked with the Netherlands Perinatal
Registry (Perined)
2013
Hiraizumi Y, et
Japanese Red Cross Katsushika
al. [32]
Maternity Hospital database
2007 2011
Homer C,
et al. [33]
Hutton EK,
et al. [28]
5 datasets in New South Wales.
NSW Perinatal data collection
NSW admitted patient data collection
NSW register of congenital conditions
NSW registry of births, deaths, and
marriages
Australian Bureau of Statistics
2000 2008
Ontario Midwifery Program dataset
2003 2006
Hutton EK,
et al. [3]
Ontario Midwifery Program dataset
2006 2009
Stratified
7
and adjusted
Matched and 7
stratified
Stratified
6
Presumed
matched,
equal
proportion
in groups by
parity
Stratified
7
Within
standards
Retrospective
cohort study
168 home
123 hospital
Japan
(Midwives less
well-integrated)
8,11 14,17,18
No
7
Within
standards
Retrospective
cohort study
735 home
221,284
hospital
2000 2008
(birth centre
outcomes
excluded)
Australia
(Midwives less
well-integrated)
1,2,4
Yes
Matched,
stratified
8
Ontario, Canada
(Midwives
well-integrated)
Ontario, Canada
(Midwives
well-integrated)
Yes
8
6692 home
6692 hospital
2003 2006
11,493 home
11,493 hospital
1 3,5,6,8 12,
14 18
Matched,
stratified
Pragmatic
Retrospective
cohort study
Pragmatic
Retrospective
cohort study
1 6,8,10 12,
14 18
Yes
(continued)
E.K. Hutton et al. / EClinicalMedicine 14 (2019) 59 70
63
Table 2 (Continued)
Study
Data source & time period
Method of
accounting
for parity
Methods
Nos
quality
score
Sample size
Setting and
degree of
integration
Outcomes
reported
Author
questionnaire
completed
Janssen P,
et al. [21]
Home: Home Birth Demonstration
Project
Hosp: British Columbia Perinatal
Database Registry
1998 1999
Matched,
adjusted
6
Pragmatic
Prospective and
Retrospective
cohort study
British
Columbia,
Canada
(Midwives
well-integrated)
1,2,6 8,11 18
Yes
Janssen P, et al.
[22]
Home: BC Perinatal Database Registry
+ Rosters submitted to the College of
Midwives of BC
Hosp: BC Perinatal Database Registry
2000 2004
Matched,
adjusted
6
Pragmatic
Retrospective
cohort study
British
Columbia,
Canada
(Midwives
well-integrated)
1,2,4,6 8, 10 18
Yes
Lindgren H, et
al. [31]
Home: Home birth midwives reports,
linked to Swedish Medical Birth
Register
Hosp: Swedish Medical Birth Register
1992 2004
Midwives who chose to participate and
report on their most recent nulliparous
births.
Not reported
St. Mary’s Maternity Information
System
1988 2000
Adjusted
6
Pragmatic
Retrospective
cohort study
862 home
571 MW
comparison
743 MD
comparison
Used MD
comparison
group
2899 home
4752 MW
comparison
5331 MD
comparison
Used MD
Comparison
group
897 home
11,341 hospital
Sweden
(Midwives less
well-integrated)
1,2,4,10 12, 16, 18
Yes
Restricted to
nulliparous
4
109 home
116 hospital
New Zealand
(Midwives
well-integrated)
11,12,14 18
No infant outcomes
Yes
Adjusted
8
5998 home
267,874
hospital
England
(Midwives
well-integrated)
11
No infant outcomes
Yes
Pang J, et al. [18] Washington State birth certificate data
1989 1996
Adjusted,
stratified
4
6133 home
10,593 hospital
No
Netherlands Perinatal Registry
2000 2007
Adjusted
7
1,2,4
Yes
van der Kooy J,
et al. [19]
Netherlands
Perinatal Registry
2000 2007
Questionnaires and the Birth
Notification System
1990 1993
Adjusted
Washington
state, USA
(Midwives
well-integrated)
Netherlands
(Midwives
well-integrated)
Netherlands
(Midwives
well-integrated)
Netherlands
(Midwives
well-integrated)
1,3,11
Data not available
for meta-analysis
van der Kooy J,
et al. [29]
Within
standards
Retrospective
cohort study
Within
standards
Retrospective
cohort study
Within
standards
Retrospective
cohort study
Pragmatic
Retrospective
cohort study
Pragmatic
Retrospective
cohort study
Pragmatic
Prospective and
Retrospective
cohort study
1, 18
Data not available
for meta-analysis
1,3,4,9,11,16 18
Yes
Miller S, et al.
[16]
Nove A, et al.
[17]
Wiegers TA, et
al. [24]
Stratified
6
402,912 home
219,105
hospital
402,912 home
219,105
hospital
1140 home
696 hospital
Yes
Outcomes reported by included studies are listed in the table as follows. Outcomes reported in this manuscript are bolded and underlined in the table.
1. Any perinatal or neonatal mortality.
2. Perinatal or neonatal mortality excluding malformations.
3. Perinatal or neonatal mortality including malformations.
4. Any perinatal mortality.
5. Any neonatal mortality.
6. Neonatal Resuscitation.
7. Apgar
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