Monday April 30 2012
Midwife numbers have risen in London, but so have deaths
“More than 100 mothers have died in childbirth in London in the last five years,” according to The Independent. The newspaper says the rate is twice as high as the rest of the country, and that a shortage of midwives may be to blame.
The news is based on a letter written to The Lancet medical journal by Susan Bewley and Angela Helleur of the Women’s Health Academic Centre at St Thomas’ Hospital London, and on subsequent interviews with Cathy Warwick, chief executive of the Royal College of Midwives. News coverage also focused on Warwick’s calls for more midwives in London, owing to a perceived shortage in the capital.
The original letter drew on a variety of data suggesting a potential rise in maternal deaths in London in recent years. The letter suggested that either poor maternity services or an increase in the number of women with pregnancy risk factors could be behind the possible rise.
While this news is potentially worrying for expectant mothers, the numbers should be viewed in context, as the chances of maternal death during childbirth are extremely low in London, at around 0.013%. That said, the research highlighted the importance of tailoring midwifery services to the needs of London women, and of ensuring that appropriate maternity services, such as midwives, are available to all.
In an interview with Behind the Headlines, Cathy Warwick sought to give reassurance as she commended the overall quality of maternity services in London, and said: "NHS London has been one of the leading Strategic Health Authorities both in ensuring high-quality maternity services and attempting to increase midwife numbers. There have been some really big efforts in London, and for the vast majority of women their care will be of a very high standard."
What did the letter say?
The letter highlighted large, regional disparities in the rates of UK women dying during childbirth, with London’s maternal mortality rate being substantially higher than in the rest of the UK. The authors presented figures suggesting that:
- London sees 19.3 deaths per 100,000 maternities (95% CI 14.0 to 26.6).
- The rate is much lower across the rest of the UK, with 8.6 deaths per 100,000 maternities on average (95% CI 7.1 to 10.5).
These figures came from a review carried out by the Centre for Maternal and Child Enquiries (CMACE) covering January 1 2009 to June 30 2010.
The letter also quoted figures suggesting that in the last decade there has been a 27% jump in the birth rate in London, up from 106,071 births in 2001 to 134,544 in 2011. The authors highlighted that birth rates in London began to rise sharply between 2005 and 2011 and that maternal mortality rates also increased.
Why have rates risen and why are they so high in London?
The expert letter does not specifically state that a lack of midwives has caused a rise in maternal deaths seen in London, as some news reports may have implied. Instead, the brief letter listed several factors linked to the risk of a mother developing life-threatening complications during pregnancy or labour, and suggested they may be particularly relevant to London’s child-bearing population.
These risk factors included:
- maternal age
- social deprivation
- being from a black or minority ethnic background
- late access to healthcare
- use of IVF
- multiple pregnancies (where the mother is carrying more than one baby)
The letter did, however, highlight how London’s maternity services may have been found “wanting” in the past compared with the rest of the UK. The authors suggested that the high mortality in London women may reflect “worsening demographic risk factors and medical risk in the pregnant population, excessive strain on the healthcare system, or both”.
How have maternal death rates changed?
Using figures from a past CMACE review, the letter reports that UK maternal mortality rates remained relatively static between 1983 and 2008, varying from about 9.8 to 13.1 maternal deaths per 100,000 maternities (maternities were defined as pregnancies resulting in live birth or stillbirth occurring at or after 24 weeks). Hence, death during maternity or birth is still a rare event, with even the highest rate during this period equating to 0.013% of births resulting in maternal death.
As well as saying that there was “a rise in maternal mortality between 2005 and 2011” in London, the letter presented a graph showing maternal mortality rates per 100,000 maternities. This graph showed a broadly rising trend from 2005/6 to 2010/11.
However, it is clear to see that the difference is not statistically significant, as the error margins of the rates are quite large and overlap from year to year. This means that the year-on-year increase in maternal mortality rates for London described in the letter may in fact be due to chance. This is not to say that such an increase has not occurred or that it should be dismissed; only that the graph presented in the letter does not prove that a rise definitely occurred or that any genuine rise in deaths may not be due to normal fluctuations that have occurred by chance.
Better data would be needed to verify whether maternal mortality rates have indeed increased in London in recent years, as the letter suggested.
Where can women give birth?
Women who are pregnant can give birth in their choice of a range of settings that suit them. These include giving birth at home, in a unit run by midwives (a midwifery unit or birth centre) or in hospital. The choice of where to give birth will depend on the mother’s needs and risks and, to some extent, where they live.
In all settings, a trained midwife will support a pregnant woman during the birth. If extra help is needed during a home birth or at a birth centre, for instance if there are complications, the midwife will arrange for transfer to hospital to receive further assistance where more expertise is on hand.
Are there fewer midwives nowadays?
The letter suggested that in the past decade maternity services have been vastly affected by mergers, reconfigurations of services and site closures, and that this may be in some way related to the rising death figures. While the letter did not state that lower midwife numbers may be to blame, the media reports have made this link and have splashed this across some headlines. In part, these suggestions seem to be based on interviews with the Royal College of Midwives, which is currently campaigning for an extra 5,000 midwives to be recruited in England.
It’s not easy to verify independently how midwife numbers have changed in recent years, although figures recently presented to Parliament indicate a rise: there were 4,509 qualified midwives in London in 2011 compared with 3,024 in London in 2001. The fact that midwife numbers have already risen makes it difficult to tell how further increases in midwives might impact on maternal mortality rates.
The exact relationship between regional midwife numbers and maternal mortality rates is hard to determine, and the sources behind much of the news coverage do not point to a definitive link between midwife staffing levels and a higher rate of maternal mortality in London. That is not to say that such a link does not exist, but that the expert opinions and selected results suggesting a link do not prove that a shortage of midwives is behind any rise in maternal death rates.
Indeed, even the rise in death rates seen in London was not “statistically significant”, which means that we cannot be sure that the rises are not just part of normal fluctuations, even if they do appear to be much higher than in areas outside of London. However, even if the rise in maternal death rates is a reflection of a genuine phenomenon, it is hard to attribute it to midwife staffing levels or another single cause. For example, as the original journal letter pointed out, it could be due to the complex demographics of London mothers, who may vary greatly in their background, health and age from mothers in other regions.
Overall, this news should not be a cause for alarm among expectant mothers, as the chances of maternal deaths in London are still extremely low, at a rate of 0.013% even in the peak year mentioned in the journal letter. Instead, the news is a reminder that local services need to be appropriately tailored to meet the needs of the people using them. There may need to be greater examination of where London maternity services can be further improved.
Cathy Warwick, chief executive of the Royal College of Midwives, sought to place London mortality rates into context. In particular, she highlighted London’s high standards in quality and safety overall: "NHS London has been one of the leading Strategic Health Authorities both in ensuring high-quality maternity services and attempting to increase midwife numbers. There have been some really big efforts in London, and for the vast majority of women their care will be of a very high standard."