Stillbirths are not just a low-income country problem. Rates in the UK and the USA have decreased by only 1% per year for the past 15 years and stillbirths now account for two-thirds of perinatal deaths (deaths before age 7 days) in the UK. In high-income countries, late gestation stillbirths (28 weeks and later) exceed deaths from sudden infant death syndrome by a factor of ten or more, but receive less attention in programmes and funding for research. The situation in high-income countries is addressed in paper 5 in the Series (Vicki Flenady and colleagues), and also in linked Articles discussing risk factors in wealthy nations and latest stillbirth estimates. More general information on stillbirths everywhere can be found in the rest of the Series.
The current variation in stillbirth rates across and within high-income countries indicates that further reduction in stillbirths is possible. Large disparities (linked to disadvantage such as poverty) in stillbirth rates need to be addressed by providing more educational opportunities and improving living conditions for women. Stillbirth rates and trends in all countries are discussed in the Article by Joy Lawn, Simon Cousens and colleagues. A spreadsheet has also been provided with country rankings for various indicators, and a contact sheet for parent stillbirth groups in various countries.
For international comparisons, it is vital to note that the World Health Organization (WHO) definition of stillbirth as 28 weeks or later is used; yet many high-income countries define stillbirths as occurring at 22 weeks or even earlier. The main exceptions are the USA and Australia (that use 20 weeks) and the UK (24 weeks). The spreadsheet that accompanies these press releases makes clear the stillbirth estimates in high-income countries for both the 28-week (often referred to as late gestation stillbirths) WHO cut-off point, and that country's own local cut-off point.
It is clear from the data that some high-income countries are performing much better than others. Using the WHO stillbirth definition, Finland and Singapore have the lowest stillbirth rate at 2.0 per 1000 total births, followed closely by Denmark and Norway. Yet Australia and the USA have rates of 2.9 and 3.0 respectively per 1000 births, and the UK rate is almost double Finland's at 3.5 per 1000 births. The high-income country with the highest (worst) rate of stillbirth is France (3.9 per 1000), with Austria second worst (3.7) and UK and New Zealand joint-third worst (3.5). The UK is only 33rd best globally in terms of its stillbirth rate, well behind most other wealthy nations and with a similar ranking to Belarus and Estonia. And while countries such as Italy have had larger reductions in their stillbirth rate from 1995 to 2009 (36% and 26% respectively), the USA, UK, France and Germany have all seen reductions below 20%. The USA sees an estimated 13070 late gestation stillbirths each year, the UK 2630, and Australia 780. If the earlier, local definitions are used, total stillbirths become 27500 in the USA (from 20 weeks); 4100 in UK (from 24 weeks); and 2190 in Australia (from 20 weeks).
Up to 58% of women of childbearing age in wealthy nations are overweight or obese, which are major risk factors for stillbirth, with an estimated 8000 stillbirths across 42 high-income nations associated with these conditions (using local country definitions for high-income countries for obesity and the other risk factors in this and the next paragraph) Of these, an estimated 4056 are in the USA, 705 in the UK, and 178 in Australia. Maternal age of over 35 years also raises the risk of stillbirth by 65% compared with women under 35. Some 4000 stillbirths in high-income countries are linked to advanced maternal age (estimates: USA 1116, UK 367, Australia 99). Around half of all pregnant women consume alcohol during pregnancy, which raises the risk of stillbirth by 40% (although data are inadequate to be confident of the size of this risk, which is likely to be higher). Being pregnant for the first time (primiparity) also contributes to about 15% of stillbirths. The authors note the increasing prevalence of women with a combination of risk factors, such as advanced age, obesity, and giving birth for the first time. Previous caesarean section may also raise the risk of stillbirth by 30%.
Any smoking during pregnancy raises the risk of stillbirth by 40%, although the authors suggest that this is likely to be a conservative estimate with some high quality data suggesting a doubling of the risk. Around 3000 stillbirths in high-income countries are linked to maternal smoking (estimates: USA 1097, UK 346, Australia 77). Smoking cessation programmes are effective in reducing smoking in pregnancy, improve newborn outcomes and should be implemented as part of routine antenatal care. The authors say: "Women should also be advised about the harms of smoking and alcohol intake and be aware that no safe level of alcohol consumption has been established."
In high-income countries, disadvantaged women still have very high stillbirth rates. For example, Indigenous women in Canada and Australia and African-American women in the US have stillbirth rates similar to women in middle-income countries. The Series makes a call for all high-income countries to address this disparity through providing programs which increase access to educational opportunities and health care which meet the needs of these women. In Australia, using the local stillbirth definition of 20 weeks or later, rates among indigenous women are around 50% higher than among non-indigenous women. The USA also has a local definition of stillbirth being 20 weeks or later.There, compared to white women and Hispanic women who have stillbirth rates of less than 6 per 1000 total birth, the stillbirth rate among African American women is 11.3 per 1000. In the UK, using the local definition of 24 weeks, Afro-Caribbean women are twice as likely (9.2 per 1000 births) to experience a stillbirth as white women (4.5).
The causes of stillbirths are discussed in papers 2 and 5 and the linked Article also from Vicki Flenady and colleagues. In high income countries around 29% of stillbirths are associated with placental problems (mainly poor placental function –insufficiency- often for reasons which are unclear and placental abruption), or other causes including umbilical cord problems (9%), infection (12%), congenital abnormalities (6%), intrapartum or birth complications (3%), direct fetal causes, including blood disorders and incompatibilities (4%), direct maternal causes such as diabetes and hypertension (7%). But the causes of 30% of stillbirths remain unknown, even in high-income settings. Suboptimal care could be a contributing factor in up to 6 in every 10 stillbirths. Failure by the medical team to use best practice protocols during birth, and inadequate antenatal appointment attendance by the mother are both examples of suboptimal care.
Intrapartum stillbirths are rare in high-income countries at around 0.5 per 1000 total births compared to around over 17 per 1000 in the 28 low income countries with a stillbirth rate of over 25.
The authors divide strategies for tackling stillbirths in high-income countries into three categories: i) improving the health and wellbeing of women before, during, and after pregnancy; ii) detection and management of women at risk during pregnancy and iii) improving access to information and standards of maternity care.
Preconception care, including adequate diet and exercise, optimum folic acid intake, and stopping smoking and alcohol consumption are all important. Education and employment opportunities are vital for disadvantaged women, who face higher incidences of risk factors and medical conditions affecting pregnancy such as diabetes. Regular attendance for antenatal care is especially important for these women, but the authors acknowledge financial and transport issues can hinder attendance. In a Comment, Gary Darmstadt from the Gates Foundation points out the importance of optimising every interaction families have with the health system to improve the health of women and reduce stillbirth.
Several studies are ongoing assessing the impact of obesity in pregnancy. Guidelines for healthy weight management are available from the UK's National Institute for Health and Clinical Excellence (NICE) and the US Institute of Medicine. Women with pre-existing diabetes have a risk of stillbirth three times that of non-diabetic women.
Stillbirths related to placental insufficiency are often associated with fetal growth restriction, and this must be screened through clinical assessment of fetal growth at regular antenatal health checks and serial ultrasound where there is clinical suspicion of growth restriction. Doppler ultrasound—used to assess fetal blood flow—should be used to monitor high-risk pregnancies, with monitoring and treatment with low-dose aspirin given to those at increased risk. There needs to increased awareness and timely clinical evaluation of women reporting decreased fetal movements. The authors note that planned early delivery, based on presence of risk factors, is increasingly used to avert late gestation stillbirths. However the authors caution about the balance of risk and benefits for early birth, noting the risks of inadvertent preterm birth and its associated morbidity and mortality. Early pregnancy ultrasound to ensure accurate dating is an important part of planning appropriate care for women including timing of birth where complications arise. Women who continue to be pregnant post term (41 weeks or more) should also be routinely offered induction. Women using in vitro fertilization (IVF) technology should limit the number of embryos implanted, since multiple pregnancies also raise stillbirth risk by between three and six times.
As many very preterm stillbirths are linked to preterm, prelabour rupture of the membranes (PPROM) and infection, antibiotics should in theory be capable of reducing stillbirths in high-income countries. Yet they have shown little effect. However, one interesting meta-analysis of stillbirths showed that treatment of dental (periodontal) disease reduced stillbirth rates by around half. But the Series authors caution that further research is needed.
In-depth analysis of each death, such as that provided by a perinatal audit, could also facilitate further reductions in stillbirth rates. A perinatal audit covers all aspects of diagnosis, treatment, use of resources and outcomes. In Norway, overall perinatal mortality has fallen 50% since 1986 when the audit was introduced. In the UK, stillbirth rates remain almost twice that of Scandinavian countries despite confidential enquiries that have taken place in the past, with the last being near the start of the Millennium.
Alarmingly, recent evidence suggests that stillbirth autopsy rates are falling in high-income countries, even though the information gained is often vital in understanding cause of death. Medical history of the mother and detailed analysis of the placenta and umbilical cord is essential. However, the evidence for other tests routinely performed is very limited and further research is urgently needed so that women are not asked to undergo unnecessary and often intrusive testing particularly at such a vulnerable time.
Despite all the global advances in science, the authors note that "a substantial proportion of stillbirths lack an obvious maternal risk factor and are thought most likely to portray an incompletely understood abnormality of placental function, which might or might not be associated with impaired growth."
The authors conclude: "Future research should focus on screening and interventions to reduce antepartum stillbirth and stillbirth associated with extremely preterm birth and infection. Identification of ways to reduce maternal overweight and obesity is also a priority for high-income countries. Effective research collaborations are needed to carry out often large scale research required to address stillbirth in high-income countries…Parents have the greatest stake of all in the wellbeing of their baby, and must be part of the drive to reduce stillbirth. Parents and health professionals working collaboratively (in such models as the International Stillbirth Alliance) have a powerful role to play in bringing stillbirth to public attention and pushing for the prioritisation of stillbirth in research and maternity services."
EXTRA INFO ON THE SERIES, INCLUDING COUNTRY BY COUNTRY BREAKDOWNS
A spreadsheet has been prepared giving country by country breakdowns and rankings. Countries are ranked by stillbirth rate in 2009 and previously in 1995; for the number of stillbirths in 2009; and in terms of average annual rate of change 1995 to 2009. In all rankings the lowest numbers are the best.
The international comparisons use stillbirth rates at 28 weeks and later, this is because WHO uses this cut-off since babies in low-income and middle-income countries are unlikely to survive if born at 28 weeks or earlier, and the data is below this cut off is highly variable in these countries. Thus the 28-week cut off allows stillbirths to be compared across countries of all incomes.
However, local definitions in high-income countries have earlier cut-off points, and thus figures according to local definition are also included. In most high-income countries, the cut-off is 22 weeks, but the key exceptions are Australia (20 weeks), USA (20 weeks) and UK (24 weeks).
Thus some high-income countries will have two rates and total stillbirth figures: one for 28 week international comparison (lower rate and number) and one according to local definition (higher). For example, the UK's rate for 2009 is 3.5 stillbirths per 1000 total births and 2630 total stillbirths using the 28 week cut-off; but using the UK's definition of 24 week cut-off, this increases to 4100 stillbirths at a rate of 5.2 per 1000 total births.
Journal
The Lancet