MBRRACE-UK perinatal mortality surveillance

1. Introduction

1.1. Report overview

This is the ninth MBRRACE-UK Perinatal Mortality Surveillance Report and the first presented as a concise “State of the Nation” report. The report is divided into five sections: perinatal mortality rates in the UK; mortality rates for Trusts and Health Boards; mortality rates by gestational age; mortality rates by ethnicity and deprivation; and a description of the causes of perinatal death.

This report focuses on births from 24 completed weeks’ gestational age, with the exception of the section on mortality rates by gestational age, which also includes information on births at 22 to 23 completed weeks’ gestational age. This avoids the influence of the wide disparity in the classification of babies born before 24 completed weeks’ gestational age as a neonatal death or a late fetal loss. Terminations of pregnancy have been excluded from the mortality rates reported.

Additional supporting materials to accompany this report include:

• a set of reference tables;
• a data viewer with interactive mapping, which presents mortality rates for individual organisations, including Trusts and Health Boards; and
• a technical manual containing full details of the MBRRACE-UK methodology, including definitions, case ascertainment and statistical methods.

A summary version of the report is also available to download as a PDF and as an infographic.

1.2. Terminology

In this report we use the terms ‘women’ and ‘mothers’. However, we acknowledge that not all people who access perinatal services identify as women, and that our recommendations apply to all people who are pregnant or have given birth. Likewise, use of the word ‘parents’ includes anyone who has the main responsibility of caring for a baby.

2. Perinatal mortality rates in the UK: 2021

2.1. Introduction

Rates of stillbirth, neonatal mortality and extended perinatal mortality are presented for the UK and for each devolved nation for the period 2013 to 2021. This is to show trends in mortality rates over time and to enable individual nations to monitor the progress of initiatives to reduce perinatal mortality,

2.2. Key messages

• Perinatal mortality rates increased across the UK in 2021 after 7 years of year-on-year reduction.
• Stillbirth rates per 1,000 total births in 2021 for the UK were 3.54 and varied between the devolved nations; 3.52 (England); 3.27 (Scotland); 3.88 (Wales); and 4.09 (Northern Ireland).
• Neonatal mortality rates per 1,000 live births in 2021 for the UK were 1.65 and rose across all of the devolved nations; 1.60 (England); 1.91 (Scotland); 1.70 (Wales); and 2.46 (Northern Ireland).

2.3. Births and perinatal deaths

In 2021, there were 698,909 total births at 24 completed weeks or greater gestational age (excluding terminations of pregnancy) for the UK. This was an increase of 9,905 births (1.5%) compared with 689,004 in 2020.

Since 2013 there has been a year on year reduction in both the total number of stillbirths and the total number of neonatal deaths. However, 2021 saw an increase in both stillbirths and neonatal deaths and their respective mortality rates. There were 2,473 stillbirths in 2021, compared with 2,292 stillbirths in 2020 and 2,399 in 2019. There were 1,151 neonatal deaths in 2021, compared with 1,051 neonatal deaths in 2020 and 1,158 in 2019.

2.4. Perinatal mortality rates across the UK

Stillbirth, neonatal mortality and extended perinatal mortality rates increased in the UK in 2021, ending the consistent reduction in UK rates since 2013. The extended perinatal mortality rate for 2021 across the UK as a whole was 5.19 per 1,000 total births (4.85 in 2020); comprising 3.54 stillbirths per 1,000 total births (3.33 in 2020) and 1.65 neonatal deaths per 1,000 live births (1.53 in 2020).

Across the four UK nations, the lowest stillbirth rate in 2020 was in Scotland (3.27 per 1,000 total births), whilst the lowest rate of neonatal mortality was in England (1.60 per 1,000 live births). For both stillbirths and neonatal deaths in 2021, the highest rates were in Northern Ireland (stillbirths: 4.09 per 1,000 total births; and neonatal deaths: 2.46 per 1,000 live births). As in previous years, the number of babies born in the Crown Dependencies is too few to permit reliable comparison with the four countries of the UK.

2.5. Impact of COVID-19 on perinatal mortality

Following the start of the SARS-CoV-2 (hereinafter referred to as COVID-19) pandemic in late March 2020, MBRRACE-UK collected additional information on the COVID-19 infection status of all mothers and babies where there was a notifiable stillbirth or neonatal death. In 2021, 351 mothers of babies who were stillborn had a positive test for COVID-19 infection. One further stillborn baby tested positive for COVID-19 infection without a corresponding positive test in the mother. In total, this made up 11.9% of the total stillbirths. Fifty seven mothers of babies who died in the neonatal period had a positive test for COVID-19 infection; 4.8% of the total number of neonatal deaths from 24 completed weeks' gestation.

However, the risk of stillbirth and neonatal death associated with COVID-19 infection cannot be calculated, as the necessary denominator data on the COVID-19 infection status for all births (and therefore all mothers) is not collected.

3. Perinatal mortality rates for Trusts and Health Boards

3.1. Introduction

To account for the wide variation in case-mix, Trusts and Health Boards were classified hierarchically into five mutually exclusive comparator groups, based on their level of service provision. In order to compare Trusts and Health Boards more fairly, stabilised & adjusted mortality rates were calculated and colour-coded according to the variation from their respective comparator group average. A complete explanation of the MBRRACE-UK methodology, including statistical methods, can be found in the technical manual.

Where there is only a small number of births in an organisation it is difficult in any one year to be sure that any extreme value seen for the crude mortality rate is real and not just a chance finding. A stabilised rate allows for the effects of chance variation due to small numbers. The mortality rates are also adjusted to account for key factors which are known to increase the risk of perinatal mortality. The extent of the adjustment is limited to those factors that are collected for all births across the whole of the UK: mother’s age; socio-economic deprivation based on the mother’s residence; baby’s ethnicity; baby’s sex; whether they are from a multiple birth; and gestational age at birth (neonatal deaths only). A complete explanation of the MBRRACE-UK methodology, including statistical methods, can be found in the technical manual.

3.2. Key messages

• As in 2020, stabilised & adjusted stillbirth rates in 2021 continued to show greater variation than in the years 2013 to 2019, with only 61.8% of Trusts and Health Boards having a stabilised & adjusted stillbirth rate within 5% of their comparator group average.
• Stabilised & adjusted neonatal mortality rates continued to show wide variation, with just 38.2% of Trusts and Health Boards falling within 5% of their comparator group average
• After the exclusion of deaths due to congenital anomalies, 49.3% of Trusts and Health Boards had a stabilised & adjusted neonatal mortality rate within 5% of their comparator group average.

3.3. Variation in perinatal mortality rates within Trust and Health Board comparator groups

Stabilised & adjusted stillbirth rates in 2021 continued to show greater variation than in the years 2013 to 2019, with 15.1% of Trusts and Health Boards having a stabilised & adjusted stillbirth rate more than 5% and up to 15% lower than their comparator group average, and 21% having a rate more than 5% higher than the average. As a consequence, only 61.8% of Trusts and Health Boards had a stabilised & adjusted stillbirth rate within 5% of their comparator group average.

Stabilised & adjusted neonatal mortality rates continued to show wide variation, with 38.2% of Trusts and Health Boards falling within 5% of their comparator group average.

3.4. The effect of congenital anomalies on perinatal mortality rates

Deaths due to congenital anomalies continue to account for a large proportion of perinatal deaths (see Section 6). Exclusion of deaths due to congenital anomalies removes a large proportion of the variation in stabilised & adjusted stillbirth rates compared to the comparator group average, with 77.0% of Trusts and Health Boards falling within 5% of the group average.

Exclusion of deaths due to congenital anomalies has a limited impact on the variation in stabilised & adjusted neonatal mortality rates, with 49.3% of Trusts and Health Boards having a rate within 5% of their comparator group average. Within the comparator group most likely to care for these babies (Level 3 NICU and neonatal surgery), only 34.6% of Trusts and Health Boards fall within 5% of the group average.

3.5 Mortality rates for Trusts and Health Boards

Mortality rates for individual Trusts and Health Boards, including comparison to their respective comparator group average, can be found in the data viewer.

4. Mortality rates by gestational age

4.1. Introduction

Mortality rates by gestational age group are presented to monitor the progress of national initiatives to reduce preterm births.

4.2. Key messages

• Preterm births (before 37 completed weeks’ gestational age) account for 75% of stillbirths and late fetal losses and 73% of neonatal deaths.
• Late fetal loss and stillbirth rates increased in 2021 compared with 2020 for all gestational age groups, except for babies born between 37 and 41 completed weeks’ gestational age.
• Neonatal mortality increased in 2021 across all gestational age groups.
• The greatest increase in stillbirth rates was in the 28 to 31 completed weeks’ gestational age group. The greatest increase in neonatal mortality rates was in the 24 to 27 completed weeks’ gestational age group.

4.3. The impact of preterm birth

Data for 2021 shows the continued impact of preterm birth in relation to both stillbirth and neonatal death rates in the UK, with 75% of stillbirths (including late fetal losses) and 73% neonatal deaths being of babies born before 37 weeks’ gestational age. Despite the increases in mortality seen in babies born at 24 to 31 completed weeks’ gestational age, the overall proportion of babies born at this gestation has remained stable over the 2016 to 2021 period.

Including babies born at 22 to 23 weeks’ gestational age, 36% of stillbirths and 46% of neonatal deaths in 2021 were extremely preterm (less than 28 weeks’ gestational age), which is a small increase in this group since 2020.

4.4. Late fetal loss, stillbirth and neonatal mortality rates by gestational age

An increase in the stillbirth rate was seen in all gestational age groups, except for babies born at 37 to 41 completed weeks’ gestational age, where there was a modest 3% reduction from 1.23 per 1,000 total births in 2020 to 1.19 in 2021. This restores the otherwise year-on-year reduction in stillbirth rates for this group, after an increase in 2020. Since 2016, this is a 22% reduction in the stillbirth rate, by far the greatest reduction of any gestational age group across this period.

The greatest increase in stillbirth rates was for babies born at 28 to 31 completed weeks’ gestational age, where there was a 12% increase from 72.98 per 1,000 total births in 2020 to 81.70 in 2021.

As with stillbirths, there was an increase in neonatal mortality rates across all gestational age groups. The greatest increase in neonatal mortality rates was for babies born at 24 to 27 completed weeks’ gestational age, where there was an 18% increase from 135.6 per 1,000 live births in 2020 to 160.0 in 2021.

4.5. Babies born at 42 weeks' gestational age or later

The small number of babies born at 42 weeks’ gestational age or later means that rates are subject to higher levels of yearly variation.

5. Mortality rates by deprivation and ethnicity

5.1. Introduction

To explore inequalities in perinatal outcomes, rates of stillbirth and neonatal death are compared for area level socioeconomic deprivation based on the mother’s postcode of residence at the time of the birth, and the baby’s ethnic group.

5.2. Key messages

• In 2021, there were notable increases in stillbirth rates for babies born to mothers from the most deprived areas (from 4.29 per 1,000 total births in 2020 to 4.69 per 1,000 total births in 2021), and for babies of Black ethnicity (from 6.42 per 1,000 total births in 2020 to 7.52 per 1,000 total births in 2021), leading to widening inequalities.
• In 2021, there were also increases in neonatal mortality rates for babies born to mothers from the most and least deprived areas, and for babies of Black, Asian and White ethnicity, leading to sustained inequalities by both deprivation and ethnicity.

5.3. Socio-economic deprivation

Figure 4 shows the continued impact of deprivation in relation to stillbirth and neonatal mortality rates in the UK. Data for 2016 to 2021 showed an increase in mortality with increasing deprivation for stillbirth. However there is a changing pattern in 2021, with an increase in stillbirth rates for babies born to mothers living in the most deprived quintile which has resulted in a widening of inequalities in stillbirth, with rates of 2.37 per 1,000 total births in the least deprived quintile compared with 4.69 in the most deprived quintile. For neonatal mortality, in 2021 rates increased for babies born to mothers from both the most and least deprived quintiles, ranging from 1.29 per 1,000 live births in the least deprived quintile to 2.15 per 1,000 live births in the most deprived quintile.

Socio-economic deprivation is measured using the Children in Low-Income Families Local Measure based on the mother’s postcode of residence at the time of birth.

5.4. Ethnicity

Stillbirth rates continue to be higher for babies of Black ethnicity (7.52 per 1,000 total births) and babies of Asian ethnicity (5.15 per 1,000 total births) compared with babies of White ethnicity (3.30 per 1,000 total births). There was a very small increase in stillbirth rates since 2020 for babies of White and Asian ethnicity, but a larger rise for babies of Black ethnicity representing a widening of inequalities. For neonatal mortality, the rate for babies of Black ethnicity increased to 2.94 per 1,000 live births, meaning this group now has the highest rate of neonatal mortality. There was a fall in the neonatal mortality rate for babies of Asian ethnicity (2.22 per 1,000 births). The neonatal mortality rate for babies of White ethnicity increased but remained lower than rates for Black and Asian ethnicities at 1.68 per 1,000 live births.

Mortality rates using more refined ethnic categories can be found in the accompanying reference tables. As the mortality rates for some groups are based on small numbers they are not presented here, and may be suppressed in the reference tables.

5.5. The combined effect of deprivation and ethnicity

Due to considerably higher proportions of babies of Black African, Black Caribbean, Pakistani and Bangladeshi ethnicity being from more deprived areas, they are disproportionately affected by the higher rates of stillbirth and neonatal death associated with deprivation. However, mortality rates for babies of Black and Asian ethnicity remain higher than for babies of White ethnicity across all five deprivation quintiles. A more detailed examination of the relationship between these two factors can be found in the MBRRACE-UK Perinatal Mortality Surveillance Report for Births in 2020.

6. Causes of perinatal death

6.1. Introduction

Causes of death are reported to MBRRACE-UK using the Cause of Death & Associated Conditions (CODAC) classification system. The CODAC system has a three level hierarchical tree for the coding of both the primary cause of death and any associated conditions. The CODAC level 1 and level 2 classification for all stillbirths and neonatal deaths is available in the accompanying reference tables.

6.2. Key messages

• The most common causes of stillbirth were placental, congenital anomalies, cord problems, and infection. There remains a high proportion of stillbirths with an unknown cause of death (33.3%).
• The most common causes of neonatal death were congenital anomalies, extreme prematurity, neurological, cardio-respiratory and infection.
• Congenital anomalies continue to contribute significantly to mortality rates, comprising 9.3% of stillbirths and 32.6% of neonatal deaths.

6.3. Stillbirth and neonatal mortality rates by cause of death

Stillbirths

The most common causes of stillbirth were placental, congenital anomalies, cord and infection, with 51.7% of stillbirths having a cause of death in one of these groups. However, there remains a substantial proportion of stillbirths where the cause of death is classified as unknown. After a steady decline in the proportion of stillbirths with an unknown cause of death between 2016 and 2019, the increase seen in 2020 continued in 2021. Unknown causes accounted for 33.3% of stillbirths, a rate of 1.18 per 1,000 total births

Placental causes made up 33.2% of stillbirths, a rate of 1.17 per 1,000 total births. The stillbirth rate for placental causes has been slowly rising since 2018, and 2021 continued this trend. The proportion of stillbirths due to congenital anomalies has remained fairly constant since 2016: 9.3% in 2021, a rate of 0.33 per 1,000 total births. Cord-related causes are relatively stable and comprised 4.7% of stillbirths in 2021, a rate of 0.17 per 1,000 total births. Stillbirths caused by infection accounted for 4.5% of deaths (3.4% in 2020), a rate of 0.16 per 1,000 total births

Neonatal deaths

The most common causes of neonatal death were congenital anomalies, extreme prematurity, neurological, cardio-respiratory and infection, with 77% of all neonatal deaths having a primary cause of death within one of these five groups. An increase in both the proportion of deaths and the neonatal mortality rate since 2020 occurred in all groups.

Congenital anomalies continue to account for a significant proportion of neonatal deaths: 32.6% in 2021 . In 2021, the neonatal mortality rate due to congenital anomalies was 0.54 per 1,000 live births, a small increase since 2020 when the rate was 0.50 but still below the rates from 2016 to 2019.

Extreme prematurity accounted for 14.2% of neonatal deaths in 2021 compared to 10.8% in 2020. This increase in the proportion of deaths due to extreme prematurity is accompanied by a corresponding increase in the neonatal mortality rate: from 0.16 per 1,000 live births in 2020 to 0.24 in 2021.

14.0% of neonatal deaths were due to neurological causes, continuing the increasing proportion of deaths in this group seen in 2020. This is reflected in a slightly higher mortality rate for the second year running, with the rate increasing from 0.20 per 1,000 live births in 2020, to 0.23 in 2021. Cardio-respiratory causes continue to make up around 9% of neonatal deaths after a small reduction in 2020, with the mortality rate in 2021 identical to 2018 and 2019, at 0.15 per 1,000 live births. Infection was the primary cause of death in 7.7% of neonatal deaths, a rate of 0.13 per 1,000 live births.

6.4. Intrapartum stillbirths and intrapartum-related neonatal deaths

Around 7% of all stillbirths occur in the intrapartum period. However, only a small proportion of these stillbirths are reported as having an intrapartum cause of death: 10% of intrapartum stillbirths (0.02 per 1,000 total births) and 0.7% of all stillbirths (0.04 per 1,000 total births)

Neonatal deaths attributed to intrapartum causes remain low at 2.2% (a rate of 0.04 per 1,000 live births in 2021). However, an additional 11.1% of neonatal deaths of babies born from 32 weeks’ gestational age (0.18 per 1,000 live births) were attributed to Hypoxic Ischemic Encephalopathy (HIE), a type of brain injury caused by lack of oxygen to the baby’s brain around the time of birth.

6.5. Post-mortem examination

Post-mortem examination (PM) was offered to parents for 98.1% of stillbirths and 87.4% of neonatal deaths. Where a PM was offered, full or limited consent was given for 52.1% of stillbirths and 28.4% of neonatal deaths. Examination by the coroner or procurator fiscal accounted for an additional 2.6% of neonatal deaths.

6.6. Placental histology

The proportion of stillbirths with a placental examination remains stable at 95.0%. For neonatal deaths on day 1 of life or where the cause of death was reported as intrapartum-related, the proportion with a placental examination increased from 78.0% in 2020 to 84.1% in 2021.

7. Recommendations and supporting data

8. Further information

8.1. Deaths reported to MBRRACE-UK

Deaths reported to MBRRACE-UK since 1 January 2013 are:

• late fetal losses: a baby born between 22 and 23 completed weeks’ gestational age showing no signs of life, irrespective of when the death occurred;
• stillbirths: a baby born at or after 24 completed weeks’ gestational age showing no signs of life, irrespective of when the death occurred;
• neonatal deaths: a liveborn baby (born at 20 completed weeks’ gestational age or later) who died before 28 completed days after birth.

These definitions also include any late fetal loss, stillbirth, or neonatal death resulting from a termination of pregnancy.

8.2. The birth cohort

In this report rates of stillbirth, neonatal death and extended perinatal death (stillbirths and neonatal deaths combined) are presented for births from 1 January 2021 to 31 December 2021; thus, neonatal deaths of babies born in December 2021 which occurred in January 2022 are included. The reporting of mortality for a birth cohort is in contrast to statutory publications, which are based on deaths in a calendar year. This method of reporting allows more accurate estimates of mortality rates to be produced as appropriate denominators are available.

8.3. Data sources

The data presented in this report is derived from a number of sources in addition to the information submitted via the MBRRACE-UK web-based reporting system: ONS, PDS, NRS, PHS, NISRA, Health and Social Services Department (Bailiwick of Guernsey), and the Health Intelligence Unit (Bailiwick of Jersey). Full details of all data sources and the case ascertainment procedure can be found in the accompanying technical manual.

8.4. Funding

The Maternal, Newborn and Infant Clinical Outcome Review Programme, delivered by MBRRACE-UK, is commissioned by the Healthcare Quality Improvement Partnership (HQIP) as part of the National Clinical Audit and Patient Outcomes Programme (NCAPOP). HQIP is led by a consortium of the Academy of Medical Royal Colleges, the Royal College of Nursing, and National Voices. Its aim is to promote quality improvement in patient outcomes. The Clinical Outcome Review Programmes, which encompass confidential enquiries, are designed to help assess the quality of healthcare, and stimulate improvement in safety and effectiveness by systematically enabling clinicians, managers, and policy makers to learn from adverse events and other relevant data. HQIP holds the contract to commission, manage, and develop the National Clinical Audit and Patient Outcomes Programme (NCAPOP), comprising around 40 projects covering care provided to people with a wide range of medical, surgical and mental health conditions. The programme is funded by NHS England, the Welsh Government and, with some individual projects, other devolved administrations and Crown Dependencies.

More details can be found on the HQIP website.

8.5. Stakeholder involvement

Organisations representing parents and families are involved in the MBRRACE-UK programme as part of the ‘Third Sector’ stakeholder group, identifying possible areas for future research and helping to communicate key findings and messages from the programme to parents, families, the public and policy makers, including through the development of lay summary reports. A full list of organisations can be found in the acknowledgements.

8.6. Attribution

This report should be cited as:

Draper ES, Gallimore ID, Smith LK, Matthews RJ, Fenton AC, Kurinczuk JJ, Smith PW, Manktelow BN, on behalf of the MBRRACE-UK Collaboration. MBRRACE-UK Perinatal Mortality Surveillance, UK Perinatal Deaths for Births from January to December 2021: State of the Nation Report. Leicester: The Infant Mortality and Morbidity Studies, Department of Population Health Sciences, University of Leicester. 2023.

Published by:

The Infant Mortality and Morbidity Studies
Department of Population Health Sciences
University of Leicester
George Davies Centre
University Road
Leicester LE1 7RH

9. Version history