Outcomes for births booked under an independent midwife and births in NHS maternity units: matched comparison study
BMJ 2009; 338 doi: https://doi.org/10.1136/bmj.b2060 (Published 11 June 2009) Cite this as: BMJ 2009;338:b2060
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Shorten and Shorten (1) and Gyte et al (2) have criticised some of
the features of the matching used in our recently reported study (3).
Shorten and Shorten state that there were differences in nutritional
status, smoking status, and alcohol consumption during pregnancy. This is
an assumption as we did not report any such differences, stating
explicitly that NHS data concerning these factors were not available. We
were able to report certain factors from the IMA database about these
factors, because they were available. These factors could, in fact, also
be similar in the NHS group. What we reported was a review of possible
factors that might explain the higher perinatal mortality rate in the IMA
group. However, even if these factors were available they would have to be
very strong confounders to explain such large differences in mortality.
Our design took account of all the strong confounding factors such as
socio-economic status, age, parity, breech presentation, twins, etc,
likely to impinge on the outcome and hence is a strength of the study
rather than a weakness.
The editorial is correct to note that there were differences between
the two groups in terms of obstetric risk from previous pregnancy, medical
complications during the current pregnancy, and incidence of breech
presentation; there were also differences in preterm birth rates, and the
incidence of low birth weight. The first three factors were controlled for
in our multivariable logistic regression; the other two, of course, are
clinical outcomes for the current pregnancy, and so could not be part of
any matching process.
We concede that there were difficulties in matching a self-selecting
atypical group with the general population, and were careful not to claim
that our results could be extrapolated. We disagree with Hassan (4): the
women in the IMA group were not, “by definition…low risk”; and we did
account for some of these self-selection factors in terms of socioeconomic
status, parity, age, and high risk factors. In any case, such self-
selection by this argument should have led to lower mortality, not higher.
Nevertheless, we did find some remarkable results. It is unlikely that
other factors that were not available could explain such large differences
in such a relatively large study. The case note review, as reported by
Gyte et al (2), is underway. We acknowledge Gyte et al’s support for our
call for urgent research into the apparently higher incidence of preterm
birth and low birth weight in the NHS cohort. This is potentially a very
serious public health and health economic issue.
1) Shorten A, Shorten B Independent midwifery care versus NHS care in
the UK (editorial). BMJ 2009;338:b2210
2) Gyte G et al Why do women book with independent midwives? Rapid
response
3) Symon A, Winter C, Inkster M, Donnan PT. Outcomes for births
booked under an independent midwife and births in NHS maternity units:
matched comparison study. BMJ 2009;338:b2060
4) Hassan S. Perinatal Death or Perineal Trauma? Rapid response
Competing interests:
AS, CW and PD are the original study authors
Competing interests: No competing interests
The acronym VIA (Validity, Importance and Applicability) points to
the obvious flaws in this study, compromised by the higher rate of home
births amongst pregnant women using an independent midwife (IM), who by
definition are low risk. Not surprisingly then they have better pregnancy
outcomes; home birth mothers are more likely to be highly motivated in
having a natural labour without drugs, interventions or the need for
ongoing care. This degree of self selection is an important confounder
which is unaccounted for, with the healthiest and most affluent women
being most likely to stomp up the thousand odd pounds it takes to employ
an IM. Bringing into question the matching of women for socioeconomic
status. Equally, data on 30% of births booked under IMs is missing from
the study, a surprisingly high proportion to be acceptable to the
statisticians of the Scottish NHS Statistics Division. Of extreme
importance, is the significantly higher rate of perinatal deaths in the IM
group, especially given their low risk status. Who cares about perineal
trauma if your life, or the life of your offspring, is at stake?
To put it bluntly, due to cost, and high risk pregnancies, most women
would not choose, or be suitable for IM care, regardless of the study
conclusions, diminishing its importance and applicability. On the surface,
the study results could be used as an advertisement ploy by IMs. However,
applying VIA shows that the results reflect poorly on IM care. I certainly
would not be the first to shout about them if I was a full member, or
indeed an honorary member, of the association myself. And I would not
recommend women going via an IM anytime soon; the last we heard mothers
went into labour with the aim of having a live baby, not an intact
bottom!!
Competing interests:
None declared
Competing interests: No competing interests
Dear Editor,
Am enthusiatic about the findings in the article(ref:BMJ
2009;338b2060)published on 11 June 2009.From my 12 years working
experience as a mother and a nurse midwife,I have observed that majority
of the mothers prefer independent midwifes'care to government
hospital.There is need for evidence based policy review especially in
developing countries to allow freedom of choice of health care services by
decentralising health care institutions and allowing independent skilled
midwife practice in the community.From the study ,it was evident that the
practice is effective in primary health care components.
As a Nurse researcher interested in exclusive breastfeeding
study,independent midwifery can be a potential intervention option in
scaling up exclusive breastfeeding in low income countries like Kenya.In
adddition, findings from other researchers have proven that exclusive
breastfeeding prevents the most killer diseases (Diarrhoea,Pneumonia)in
children under 5 years.
Yours sincerly,
Norah M.Nyanga
MCHD,KRCHN administrator
norahnyanga@yahoo.com
Competing interests:
None declared
Competing interests: No competing interests
Several issues arise from the recent publication on ‘Outcomes for
births booked under an independent midwife and births on NHS maternity
units: matched comparison study’ (1).
Firstly, there are weaknesses in the methodology and in the reporting
of the results. Symons at al. (1) made considerable efforts to try to
compare ‘like with like’, but as identified in the BMJ editorial in the
same issue, “...the matching process was largely unsuccessful with
numerous important differences remaining...” and it “...leaves discussion
about perinatal deaths hazardously speculative.” (2). So the comparative
findings of the study remain uncertain and it is disappointing that Symons
et al. chose to report odds ratios for groups of women who were not
adequately matched in terms of risk factors. Also the authors chose not to
wait for the completion of the case reviews of the infant deaths reported
in this study (3) which could have provided fuller information to help
interpret their findings.
Although the matching issues make comparisons between the two groups
highly problematic, the research raises important questions about the
provision of services by the NHS. We support Symons’s call for a review
into the reported higher rate of preterm birth, low birthweight and
admissions to neonatal intensive care identified in the NHS group. If
substantiated, rather than arising from confounding or matching problems,
this would have important consequences for public health due to the high
numbers of women using NHS services. In particular, there is considerable
perinatal morbidity associated with preterm birth.
A third important point to consider is why some women in the UK seek
out and pay for maternity care from an independent midwife rather than
using NHS services which are free at the point of use. It is likely that
some women are unable to get the kind of care they want and need from the
NHS, and some of them may have been traumatised by a previous birth
experience within the NHS. Of these women, some accept what the NHS
offers because they do not know about alternatives, cannot afford them,
or, perfectly understandably, do not have the confidence to question or
challenge the advice they are given. Others vote with their feet and make
arrangements for care with an independent midwife (4). Independent
midwives aim to work holistically, providing a continuous supportive
relationship throughout pregnancy, birth and the postnatal period and
taking into account a woman’s individual circumstances. Few women having
their baby in the NHS have this degree of individualised care and
opportunity to build a trusting relationship with their midwives. The main
exceptions seem to be women cared for by midwives carrying an individual
caseload and some of those booking for a home birth (5). NHS managers
must make it easier for all women, including those at higher risk of
complications, to access supportive models of care within the NHS, with
greater choice, more responsiveness and higher regard for issues of
humanity. NHS managers should also make it easier for midwives to work in
this way without having to make personal sacrifices.
References
1. Symons A, Winter C, Inkster M, Donnan PT. Outcomes for births booked
under an independent midwife and births in NHS maternity units: matched
comparison study. BMJ 2009;338:b2060
2. Shorten A, Shorten B. Independent midwifery care versus NHS care in the
UK. BMJ 2009; 338: b2210.
3. Kirkham M. June 2009. Personal communication
4. Independent Midwives UK. http://www.independentmidwives.org.uk/. Last
accessed 24 June 2009.
5. McCourt C, Page L, Hewison J, et al. Evaluation of one-to-one
midwifery: women's responses to care. Birth 1998;25(2):73-80.
Competing interests:
None declared
Competing interests: No competing interests
I read with greatest interest the research paper by Symon et al. on ‘outcomes for births booked under an independent midwife (IMA) and births in NHS’. The researchers reported that unassisted vertex delivery, spontaneous labour, use of pharmacological analgesia, perineal trauma, and breast feeding were significantly better in the IMA cohort than that of NHS though the significantly higher perinatal mortality rate among the high risk births in the IMA group is alarming. This study was conducted in the United Kingdom, a country with a well organized health care system.
Nevertheless, I see that there is huge potential to conduct similar studies in low-income countries, particularly in the sub-Saharan region, where maternal cases in health centers are mainly attended by midwives and nurses, while maternal cases in hospitals are almost entirely delivered by physicians. On top of this, task-shifting is being introduced in low-income countries to increase population access to basic health services and to help reduce preventable maternal and child mortality. Task shifting includes the delivery of community-based health promotion and preventive services by non-traditional health personnel who have only a few months of training. A study in a setting such as Ethiopia, where task shifting is taking place in combination with the provision of care by different providers would help us tease apart the differential impact of these providers on maternal and neonatal health outcomes. This in turn would provide much needed scientific evidence for challenging health human resource policies.
Competing interests:
None declared
Competing interests: No competing interests
I was amused to see that the 'pico' version of this article in the
print journal was
accompanied by an editorial co-authored by Shorten and Shorten!
Unfortunately this gem was lost in the website.
Yours humorously,
Helene Brandon
Competing interests:
The author is only 155cm in
height
Competing interests: No competing interests
Independent Midwives UK (IM UK formally IMA) welcomes the findings of
the study that show the normal birth rate and established breast feeding
at six weeks for both high and low risk women cared for by independent
midwives is dramatically higher than a cohort of women cared for by the
NHS in Scotland. Low risk women are no more likely to experience a
stillbirth or a neonatal death if they are cared for by an independent
midwife. The apparent increased perinatal mortality rate for babies of
high risk mothers needs further investigation and IM UK welcomes the case
review study currently in progress to explore the possible reasons.
IM UK does however have major concerns about aspects the study.
Primarily there is no report of the full study to refer for details
necessary to effectively critique this article. The lack of a detailed
report would also make the study impossible to reproduce.
The size of the study severely limits its value when looking at
mortality rates. IM UK concerns are reflected in a recently published
article highlighting the risks of drawing conclusions from studies that
are weak in their design and methodology. (Estimating intrapartum-related
perinatal mortality rates for booked home births: when the ‘best’
available data are not good enough. G Gyte, et al BJOG Vol116, Issue 7, p
933-942 May 2009)
Issues such as whether the NHS cases were selected by computer or
manually to match the IMA cohort cannot be clarified and therefore bias
cannot be excluded.
Poor data collection in the NHS also makes a comparative study almost
impossible. For example home births were not recorded in the Scottish data
unless the woman was transferred to hospital following the birth.
www.isdscotland.org/ Data about the use of different methods of
pharmacological analgesia (Entonox, opiates, epidural) is not available
for the NHS cohort, making only a generalised comparison possible and even
then, this relied on an incomplete data set. Breast feeding rates were
only recorded at the time of discharge from hospital in the NHS and this
was also incomplete but the figures are compared with the IMA cohort at
six weeks.
In the interest of safety and choice, IM UK urges the government to
ensure that independent midwives have access into NHS hospitals to care
for women the NHS will not support to give birth normally. Women with high
risk pregnancies such as breech and twins are increasingly told that a
vaginal birth is not an option within the NHS. Hiring an independent
midwife, who is skilled in these births, is often the only option.
However, most NHS organisations will not allow independent midwives to
deliver babies in their hospitals, forcing women to choose between a
caesarean in hospital or a high risk birth at home.
Independent Midwives UK
Competing interests:
Independent Midwives UK (formally IMA)
Competing interests: No competing interests
Re: Perinatal Death or Perineal Trauma?
I am perturbed by the suggestion that women who seek independent
midwifery care might have to choose between an intact perineum and a
living infant, and would be interested to read the rates of perineal
trauma from the correspondent's hospital.
Competing interests:
normality in childbirth
Competing interests: No competing interests