UNSW Embryology

Normal Development- Birth - Stillbirth and Perinatal Death

© Dr Mark Hill (2008)

Acknowledgements

Introduction

Stillbirth and perinatal death can be classified by a number of different systems, all still have "unexplained" or "other" as a potential option. in several systems contribute to many of these deaths. Neonatal deaths include a broader age range of infants who have also died after birth from various causes.

Early Neonatal Mortality (data, World Health Organization, 2005, World Health Report)

The distorted world map above shows the relative distribution of early neonatal death by country. Note the over-representation of Africa and Asia compared with Europe, USA and Australia. (Image: Dorling D. Worldmapper: The Human Anatomy of a Small Planet PLoS Medicine Vol. 4, No. 1, e1)

Stillbirths with a gestational age of 28 weeks or more are defined as "late fetal deaths".

There are several death classification systems used in different countries around the world, the most recent are the suggested ReCoDe (UK, 2005) and the modified Whitfield (Australia/New Zealand, 2004) systems. A common stillbirth classification is still "unexplained", with recent analysis of data showing fetal growth restriction is a common antecedent. (More? Fetal Origins Hypothesis)

Fetal growth restriction and developmental abnormalities (covered on page 2 in all Notes sections)

Some Recent Findings

Perinatal Mortality 2006 - Confidential Enquiry into Maternal and Child Health 2006 (UK) released 2008.

United Kingdom neonatal death is due mainly to immaturity (47%), lethal or severe congenital anomalies (23%) and infection (10%). The subsequent neonatal death rate (/1,000 live births) has been decreasing in recent years (3.9 in 2000, 3.5 in 2005, 3.4 in 2006). Stillbirth rate has not changed (5.3 / 1000 total births) with major causes: severe or lethal congenital abnormalities (16%), antepartum haemorrhage (9%), and intrapartum causes (8%). (More? 2005 United Kingdom Data)

Link: Confidential Enquiry into Maternal and Child Health

Balchin I, Whittaker JC, Patel RR, Lamont RF, Steer PJ. Racial variation in the association between gestational age and perinatal mortality: prospective study. BMJ. 2007 Mar 2

"Prospective study using logistic regression analysis. ...The most important factor associated with antepartum stillbirth among white women was placental abruption, but among South Asian and black women it was birth weight below 2000 g."

Australian Data

NSW Statistics (Graph: Report of the New South Wales Chief Health Officer, 2004)

In Australia, (2002) the national fetal death rate was 6.7 per 1,000 births, the neonatal death rate was 3.1 per 1,000 live births and the perinatal death rate was 9.8 per 1,000 births (More? Australian Data).

2002: fetal death rate was 6.7 per 1,000 births | neonatal death rate was 3.1 per 1,000 live births | perinatal death rate was 9.8 per 1,000 births

2001: fetal death rate was 6.9 per 1,000 births | neonatal death rate was 3.2 per 1,000 live births | perinatal death rate was 10.1 per 1,000 births

2000: fetal death rate was 7.0 per 1,000 births | neonatal death rate was 3.1 per 1,000 live births | perinatal death rate was 10.0 per 1,000 births

1999: fetal death rate was 7.0 per 1,000 births | neonatal death rate was 3.2 per 1,000 live births | perinatal death rate was 10.1 per 1,000 births

(National Perinatal Statistics Unit AIHW Data, note some data were incomplete)

NSW Data

In New South Wales (2002) 613 perinatal deaths were reported.

Unexplained antepartum deaths: 26.3% of perinatal deaths (or 39.2% of stillbirths)
Spontaneous preterm labour: 20.6% (less than 37 weeks gestation)
Congenital abnormality: 16.8%
Antepartum haemorrhage: 8.5%
Specific perinatal conditions: 7.3%, of which twin-twin transfusion accounted for 2.3% of deaths
Hypertension (high blood pressure): 5.5%
Perinatal infection: 4.4%
Maternal disease: 4.4%
Hypoxic peripartum death: 3.8%

Neonatal deaths: extreme prematurity was most common cause (39.6%), followed by congenital abnormality (19.3%), neurological disease (13.4%), cardio-respiratory conditions (11.9%), and infection (8.4%). (Data: Report of the New South Wales Chief Health Officer, 2004 accessed 19Oct05)

(More? Compare this data with that of UK Stillbirths 2005)

Links: 2007 Brochure - NSW Information for parents about the post-mortem examination of a stillborn baby

United Kingdom

The most current data comes from a report released in 2008, Perinatal Mortality 2006 - Confidential Enquiry into Maternal and Child Health (UK).

United Kingdom neonatal death is due mainly to immaturity (47%), lethal or severe congenital anomalies (23%) and infection (10%). The subsequent neonatal death rate (/1,000 live births) has been decreasing in recent years (3.9 in 2000, 3.5 in 2005, 3.4 in 2006). Stillbirth rate has not changed (5.3 / 1000 total births) with major causes: severe or lethal congenital abnormalities (16%), antepartum haemorrhage (9%), and intrapartum causes (8%).

Earliert data comes from a report released in 2007, Confidential Enquiry into Maternal and Child Health Perinatal Mortality 2005: England, Wales and Northern Ireland. The report shows that the United Kingdom's stillbirth rate has recently stopped declining possibly due to the continuing increase in the average age of British mothers. The graphs and information below are derived from this report.

UK Confidential Enquiry into Maternal and Child Health (2005)

Sample statistics from within the report:

200 pregnancies ended in a stillbirth (3600 deaths per year)
1 in 300 babies died in the first four weeks of life.
Stillbirth rate: 4.8 per 1000 (white mothers), 11.6 per 1000 (black mothers), 8.9 per 1000 (asian mothers), 4.1 per 1000 (chinese mothers).
More than half of stillbirths were classified as "unexplained"
48% of neonatal deaths were classified as caused by "immaturity"
Perinatal deaths investigated by postmortem: (2005 39%) (1993 58%)

(Data and Graphs: Confidential Enquiry into Maternal and Child Health Perinatal Mortality 2005: England, Wales and Northern Ireland. CEMACH: London; 2007 accessed 29Apr07)

Canada Data

Canadian Institute for Health Information (CIHI) report, Giving Birth in Canada, "has resulted in the lowest perinatal mortality we have ever reached." (2004)

Perinatal mortality rate /1000 total births, neonatal mortality rate /1000 live births (estimated for 1975 and 1976).

(Data: CIHI Report - Giving Birth in Canada, graph modified from CMAJ - Canada achieves lowest perinatal mortality ever)

Stillbirths (2003)

Stillbirths with a gestational age of 28 weeks or more (late fetal deaths) remained virtually unchanged in 2003 compared with the previous year.
In 2003, 1,027 children were stillborn, one less than in 2002. The 2003 level was the lowest ever.
Late fetal deaths were 3.1/1,000 total births in 2003 (live births plus stillbirths of 28 weeks or longer gestation). This was the same rate as in 2002.
Rate of late fetal death has remained below four deaths for every 1,000 total births since 1990.

(Data: Statistics Canada - Tuesday, July 12, 2005)

United States of America Data

The USA has a National Vital Statistics System, the most recent revisions are the 2003 Revised Standard Certificates and Reports (More? U.S. Fetal Death).

Links: US National Vital Statistics System

Modified Whitfield

In Australia a modified Whitfield classification is currently used.

"...Whitfield obstetric antecedent classification has shortcomings, it was not hierarchical and did not accommodate more recent knowledge about the causation of some perinatal deaths." Modifications of the Whitfield system were made and published independently (by SA, Qld committees and National Women's Hospital report).

The November 2004 revision includes the ability to classify factors associated with perinatal death. Following classification of the main obstetric antecedent factor according to the PSANZ-PDC, and in addition for neonatal deaths the neonatal factor according to the PSANZ-NDC, it is now recommended that up to two associated factors can be recorded using the classifications. (modified from: Perinatal Society of Australia and New Zealand, Clinical Practice Guideline for PNM Section 7.pdf)

The major classification groupings are listed below, each group has a subclass listing (More? subclass listing).

PSANZ Perinatal Death Classification (PSANZ-PDC)

1. Congenital abnormality (including terminations for congenital abnormalities)

2. Perinatal infection

3. Hypertension

4. Antepartum haemorrhage (APH)

5. Maternal conditions

6. Specific perinatal conditions

7. Hypoxic peripartum death (typically infants of > 24 weeks gestation or >600g birthweight)

8. Fetal Growth Restriction (FGR) (More? Intrauterine Growth Retardation)

9. Spontaneous preterm (less than 37 weeks gestation)

10. Unexplained antepartum death

11. No obstetric antecedent

(More? subclass listing)

PSANZ Neonatal Death Classification (PSANZ-NDC) (More? subclass listing)

1. Congenital abnormality (including terminations for congenital abnormalities)

2. Extreme prematurity (typically infants of less than 24 weeks gestation or less than 600g birthweight)

3. Cardio-respiratory disorders

4. Infection

5. Neurological

6. Gastrointestinal

7. Other

(More? subclass listing)

ReCoDe

The Relevant Condition at Death (ReCoDe) classification system reduces the predominance of stillbirths currently categorised as unexplained. The following is text extract is from Gardosi, 2005.

"By the ReCoDe classification, the most common condition was fetal growth restriction (43.0%), and only 15.2% of stillbirths remained unexplained. ReCoDe identified 57.7 % of the Wigglesworth unexplained stillbirths as growth restricted. The size of the category for intrapartum asphyxia was reduced from 11.7% (Wigglesworth) to 3.4% (ReCoDe)." Gardosi, 2005

ReCoDe Classifications

Fetus: (Group A)

Lethal congenital anomaly
Infection

Chronic
Acute

Non-immune hydrops
Isoimmunisation
Fetomaternal haemorrhage
Twin-twin transfusion
Fetal growth restriction* (More? Intrauterine Growth Retardation)

Umbilical cord: (Group B)

Prolapse
Constricting loop or knot
Velamentous insertion
Other

Placenta: (Group C)

Abruptio (More? Abruptio Placenta)
Praevia (More? Placenta Previa)
Vasa praevia (More? Vasa Previa)
Other "placental insufficiency"
Other

Amniotic fluid: (Group D)

Chorioamnionitis
Oligohydramnios
Polyhydramnios
Other

Uterus: (Group E)

Rupture
Uterine anomalies
Other

Mother: (Group F)

Diabetes
Thyroid diseases
Essential hypertension
Hypertensive diseases in pregnancy
Lupus or antiphospholipid syndrome
Cholestasis
Drug misuse
Other

Intrapartum: (Group G)

Asphyxia
Birth trauma

Trauma: (Group H)

External
Iatrogenic

Unclassified: (Group I)

No relevant condition identified
No information available

(Modified from Box 1 Gardosi, 2005)

Wigglesworth

This classification system for perinatal mortality analysis has a pathophysiological approach. Functional subgrouping does not consider conditions in pregnancy, during labor or in the neonatal period. In at least one study this classification system has "unexplained" stillbirths as greater than 66%.

Nordic-Baltic

The Nordic-Baltic classification is based on five variables.

lethal malformation
time of death in relation to delivery (before, during and after)
birthweight growth retardation (below mean - 2 S.D.)
gestational age
Apgar score (below or equal to / above 7 after 5 min)

Aberdeen

The Aberdeen classification is based on seven variables, this system concentrates on maternal factors, but also includes fetal malformation and infant birthweight. In this system perinatal deaths that are unexplained or related to fetal factors are grouped as miscellaneous, uncertain or unclassified.

References

Reviews

Chan A, King JF, Flenady V, Haslam RH, Tudehope DI. [See Related Articles] Classification of perinatal deaths: development of the Australian and New Zealand classifications. J Paediatr Child Health. 2004 Jul;40(7):340-7.
Yu VY. [See Related Articles] Global, regional and national perinatal and neonatal mortality. J Perinat Med. 2003;31(5):376-9.
Victora CG, Barros FC. [See Related Articles] Infant mortality due to perinatal causes in Brazil: trends, regional patterns and possible interventions. Sao Paulo Med J. 2001 Jan 4;119(1):33-42.
Khong TY. [See Related Articles] A review of perinatal autopsy rates worldwide, 1960s to 1990s. Paediatr Perinat Epidemiol. 1996 Jan;10(1):97-105; discussion 106-9.

Articles

Costello A, Osrin D. [See Related Articles] Epidemiological transition, medicalisation of childbirth, and neonatal mortality: three Brazilian birth-cohorts. Lancet. 2005 Mar 5-11;365(9462):825-6.
Morrison S. [See Related Articles] Canada achieves lowest perinatal mortality ever. CMAJ. 2004 Oct 26;171(9):1030. No abstract available. Erratum in: CMAJ. 2005 Jan 4;172(1):19
Leuthner SR, Boldt AM, Kirby RS. [See Related Articles] Where infants die: examination of place of death and hospice/home health care options in the state of Wisconsin. J Palliat Med. 2004 Apr;7(2):269-77.
Serenius F, Winbo I, Dahlquist G, Kallen B. [See Related Articles] Regional differences in stillbirth and neonatal death rate in Sweden with a cause-of-death specific analysis. Acta Paediatr. 2001 Sep;90(9):1062-7.