Download A Heazell Why babies die

Why babies die –
Update on current research
Dr Alexander Heazell
Senior Clinical Lecturer in Obstetrics
Maternal and Fetal Health Research Centre,
University of Manchester, UK
Definitions of Stillbirth
• In the UK stillbirth is defined as an infant born
without signs of life after 24 completed weeks
gestation (500g)
• Large international variation
– 16 to 28 weeks gestation
• WHO definition infant born without signs of
life after 28 completed weeks’ gestation
(1000g)
The Scale of the Problem
• WHO estimate 2.6 million stillbirths per year
(2009)
• 98% occur in low or middle-income countries
• Only 2% of stillbirths counted through
registration systems
• Estimate may be as many as high as 3.79
million per annum
WHO , 2011
We’re ok in HICs though?
•
•
•
•
•
UK stillbirth rate is 33rd out of 35 HICs
UK – 5.2 per 1,000 live births
Eire – 4.0 per 1,000 live births
Scandinavia – 2.0-3.0 per 1,000 live births
Room for improvement
Flenady et al. Lancet 2011; 377: 1703–17
Changes in Stillbirth
• Global reduction in stillbirth reduced by 14%
from 1995-2009
• Infant mortality has reduced from 63 to 35
deaths per 1,000 births from 1990-2012
• MDG 4 – Reduce Child Mortality
• In UK, stillbirths reducing by 1.1% per year
• Neonatal death reducing by 2.1% per year
• The ratio of stillbirth : neonatal death used to be
50%:50%, now approximately 60%:40%
Changes in UK Stillbirth Rate over Time
100
7
90
80
Number of Events
Number of Events
70
6
5
60
50
40
4
Stillbirth Rate
Number
of SBofx1000
Number
Stillbirths x1000
3
Number
of Live
Births x 10000
Stillbirth
Rate
30
2
20
10
1
0
0
1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010
Year
Year
ONS Data, 2013
Why do babies die?
• Understanding central to reducing stillbirths
• Difficult to assess, must consider:
– Causation – “pathophysiologic entity initiating the
chain of events that irreversibly led to death”
– Association – pathophysiological entity present at
and likely to have played a role in the death
– Incidental finding
• Obtaining information
• Classification of deaths (Classification system)
Stillbirth Certificates do not Reflect Cause
• Analysis of Medical Certificates of Stillbirth
issued in the NW region in 2009
• Compared to classification of death by panel
• 229 death certificates (16 fetocides excluded)
• Agreement on cause of death between
certificate and panel “fair” (K=0.29)
• Agreement on gestation of death between
certificate and panel “almost complete
agreement” (K=0.88)
Cockerill et al. Paediatric Perinatal Epidemiology 2012;26(2):117-23.
Differences between Certificate and Review
Cockerill et al. Paediatric Perinatal Epidemiology 2012;26(2):117-23.
Frequency of Errors on Stillbirth
Certificates
• 77.9% of stillbirth certificates had some form
of error
Cockerill et al. Paediatric Perinatal Epidemiology 2012;26(2):117-23.
Has stillbirth changed?
Primary ReCoDe
100%
UNKNOWN
90%
80%
70%
ABRUPTION
60%
50%
40%
IUGR
30%
20%
10%
ANOMALIES
0%
1986-1996
N=281
2009-2011
N=81
Heazell et al. Unpublished data
Has stillbirth changed?
Secondary ReCoDe
100%
90%
MEDICAL
80%
DISORDERS
70%
60%
PLACENTAL
50%
INSUFFICIENCY
40%
30%
20%
10%
0%
1986-1996
2009-2011
N=281
N=81
Heazell et al. Unpublished data
Classification Systems
• AttemptPurpose
to group stillbirths
according to cause
Group
Examples
#
Principal
Intended as new
INCODE, PSANZ, Codac,
8
• Understand
causes, frequency,
trends
systems
systems
Recode, Tulip,
Stockholm
• Systematic review of classification systems
New
Combine the results Lawn 2005/2009, Gordijn 4
– 29 classification
systems created or modified
approaches
of multiple systems
2004-2013
VA validity
To test/improve VA
– 20 pre-existing
Group COD
Aggarwal 2011/2013,
Edmond,
InterVA
classification
systems
To assess COD in a
specific group
HIC datasets (4), LMIC
datasets (9)
4
13
Leisher S et al. International Stillbirth Alliance Meeting, Viet Nam, 2013
Shortcomings of Classification Systems
• Few are designed for / used in countries with
high stillbirth rates (4 out of 10)
• <20% tested for reliability, <15% for validity
• 50% have 1 cause of death
• 33% have 3 levels, averaging 12, 50 and 126
causes of death per level
• 33% of systems are hierarchical (one cause is
automatically assumed to supercede another)
• In other words, little agreement, validity or
comparability
Leisher S et al. International Stillbirth Alliance Meeting, Viet Nam, 2013
Comparison of Classification Systems
• 154 stillbirths in single institution
• Used 4 different classification systems
– Wigglesworth, ReCoDe, de Galan-Roosen, TULIP
• Institutional protocol to determine cause
– Placental histology – 77.3%
– Autopsy/PM – 24.7%
– Chromosomal analysis – 11.7%
– Infection screen including TORCH – 18.8%
Vergani et al. Am J Obstet Gynecol 2008;199(3):319.e1-4.
45.5%
14.3%
18.2%
16.2%
Investigations to Determine Cause
• Three investigations provide most useful
information to aid classification
– Autopsy / Post-mortem examination – 72.6%
– Placental histology - 95.7%
– Chromosomal analysis – 29.0%
• Value depends upon classification system used
Korteweg FJ, Erwich JJHM, Timmer A, et al. Am J Obstet Gynecol 2012;206:53.e1-12.
Placental Examination
• Histological examination of the placenta reduces
the chance of having an “unexplained stillbirth”
(OR 0.17, 95% CI 0.04-0.7)
Suboptimal Care and Perinatal Audit
• Need to be aware that some babies die due to
suboptimal maternity care
• Local review of perinatal deaths
– Why did the baby die?
• What conditions were present?
– Were there any avoidable factors?
• Major: Factor contributed significantly to the death. Different
management would reasonably have been expected to alter the
outcome.
• Minor: Factor was a relevant contributory factor. Different
management might have made a difference, but survival was
unlikely in any case.
• Irrelevant: Although lessons can be learned, it did not affect the
eventual outcome.
Confidential Enquiry / Case Review
• Essential component of perinatal audit
• Confidential Enquiry of 422 cases of stillbirth
in 1996/7 (8th CESDI report)
Confidential Enquiry of Perinatal Deaths
in Cumbria
• Review commissioned by NHS Cumbria
• Anonymised case notes discussed by
multidisplinary expert panel
• 60 cases available for discussion
– 63% of cases had some evidence of avoidable
factors
– 33% of cases had a least one major avoidable
factor
Confidential Enquiry – Case
• Mary was in her late thirties; she had 2 children aged between 2 and 5. At
the time of booking her BMI was 30, she smoked but declined the smoking
cessation programme. Mary booked at 12 weeks gestation and was
assessed as low risk and was booked for midwifery led care. She was seen
regularly and monitored by her community midwife.
• At 37+3 weeks’ gestation Mary complained of reduced fetal movements,
she was seen at her local maternity unit where CTG monitoring was
performed. She was discharged home a couple of hours later after a
reassuring CTG.
• At 39 weeks gestation Mary rang her midwife complaining of contractions
and on questioning reported no fetal movements for several hours, her
midwife advised her to attend the local hospital where unfortunately a
fetal death in utero was identified.
• Labour was induced and Mary delivered a stillborn male with a birth
weight of 2.4kg. Mary declined post mortem, but agreed to have her
placenta examined.
Confidential Enquiry – Review Findings
• Mary’s previous child was born at term and weighed
2.45 kg, which was small for gestational age. This was
not picked up as a risk factor.
• Mary reported reduced fetal movements: she had a
CTG but not an ultrasound scan.
• There was no evidence from the notes that Mary was
advised about being aware of changes in her baby’s
movements . Mary rang the midwife complaining of
contractions, fetal movements appeared secondary to
her concerns.
• Placental pathology was performed but in the opinion
of the perinatal histopathologist this was inadequate.
Confidential Enquiry in Cumbria
Importance of Understanding Why
Flenady et al. Lancet 2011; 377: 1703–17
What conditions are associated with
Stillbirth in Manchester?
So why do babies die?
• Big Three Primary Factors
– Fetal Growth Restriction and Placental Failure
– Infection
– Lethal Congenital Abnormality
• Poor at predicting and identifying FGR
– Recognition and Treatment of high-risk status
• Poor at communicating and engaging with
BME groups (37% of SBs)
Conclusions
• Understanding why babies die is critical to
prevention of stillbirth
• Appropriate Investigation
• Perinatal Audit - Identify conditions cause /
associated with stillbirth
– Fetal Growth Restriction
– Infection
• Confidential Enquiry – Ensure care optimal
• Develop relevant local strategies