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http://www.theaustralian.news.com.au/common/story_page/0,5744,16470902%255E23289,00.html
Infant formulas WOULD you entrust your
pregnant pet to the care of a midwife? The question sounds absurd but, strange
as it sounds, it seems not everybody would. More alarming,
because it was apparently factually unimpeachable, was the assertion by NSW
obstetrician Andrew Pesce in The Australian this
week that, according to an international study, women giving birth in birth
centres had "an 85 per cent higher risk of perinatal mortality overall".
To the fury of
midwives, Pesce hit the airwaves the following morning (by which time his
statistic had fallen by two percentage points), telling breakfast television
viewers the study "found an 83 per cent increased risk of a baby dying
during or immediately after childbirth". The claim was promptly
contradicted by one of the study's co-authors, who pointed out the finding was
only a trend and was not statistically significant. Midwifery
groups, meanwhile, have their evidence: the most recent being a study published
in the British Medical Journal in
June. It found that among 5418 American women who had planned home births,
there were lower rates of medical interventions and (contrary to Pesce's
figures) rates of baby deaths similar to equivalent births in hospitals.
A review of
birth-centre outcomes in the British National Health Service in December last
year found "no reliable evidence about clear benefit or harm associated
with birth-centre care compared with any other type". But as those
attending yesterday's conference in So far there
are two in NSW, at Ryde and Belmont, south of Ryde and
Belmont accept only low-risk women. Even high blood pressure during pregnancy
is deemed significant enough to require transfer to a conventional hospital.
Stand-alone units are not located within or on the same site as established
tertiary hospitals. This means that no specialist obstetricians are on site,
although they are on call. There are no anaesthetists, so no anaesthesia such
as epidurals are offered; and there are no pediatricians immediately to hand. Some
obstetricians claim all this is a recipe for potential disaster. But good
medical practice is all about evidence, so what evidence is there that
stand-alone midwifery is unsafe? Both sides trumpet studies that appear to back
their case, so who should the public believe? It's important
to first understand the terms of the debate. As the standards-setting body, the
Royal Australian and New Zealand College of Obstetricians and Gynecologists,
makes clear, midwife care per se, or midwife units attached to large hospitals,
are not the issue because in those cases back-up is available. The college
opposes stand-alone units in metropolitan areas on the grounds that transfer by
ambulance may take too long in an emergency. RANZCOG president Ken Clark says
the college has "no problem with women delivering in midwife-led
units". "If there
are more midwife-led units in Of course,
whether that's the only issue for obstetricians is another matter: the then
president of the Queensland branch of the Australian Medical Association, David
Molloy, caused a storm in May when he said the midwife unit of a Brisbane
hospital had been referred to by others as "the killing fields",
notwithstanding its hospital link. Molloy
apologised for the comment, but many midwives took the remark as symptomatic of
a deep-seated disregard for them among some doctors. It certainly fuelled a
belief that the dispute is also about the two professions' attempts to win
power over the other, a sensitive issue that was a subtext at yesterday's
conference. And when it
comes to looking at the evidence, two things are clear. One, there's relatively
little of it, and two, there are good studies and then there are less good or
relevant studies. How good, and how relevant, is often frustratingly difficult
to pin down. Both sides
often resort to referring to trials of other models of midwifery care, inviting
the argument that the model is irrelevant. In most cases the trial is from
overseas, creating another concern that the results may be inapplicable in There's an
official hierarchy of medical studies, ranking them according to methodology.
Top of the tree are what's called randomised controlled trials, where the
subjects are divided randomly into two groups, one of which receives a
treatment or procedure, and a control group that doesn't. Even better
than individual RCTs are systematic reviews of many RCTs on the same subject,
ironing out differences between them and vastly increasing sample size. Reviews
such as this are carried out by the Cochrane Collaboration; it was a Cochrane
review that Pesce used for his claim that midwife units increased the risk of
perinatal death. Had that finding been statistically significant, it would have
been much closer to the slam-dunk that Pesce was after. There are few
trials in the international literature of stand-alone midwife units. The NHS
review identified three, examining perinatal baby deaths, of which one was the
Cochrane review Pesce quoted. The other two were classified as much less
reliable. The Cochrane review Pesce quoted looked at six trials, randomised but
not controlled, three of which were very small and only one of which was
Australian. These trials involved 8677 women, but none compared freestanding
birth centres with conventional hospital care, the crux of the debate. Instead,
the trials were of births in a "home-like setting" handled by
midwives, usually birth units within hospitals. The review
found statistically significant evidence of modest benefits from midwife care,
including fewer interventions, lower rates of vaginal or perineal tearing,
greater satisfaction with care and higher rates of breastfeeding after birth.
It found a "trend towards higher perinatal mortality in the home-like
setting", and said health workers and patients "should be vigilant
for signs of complications". It also said that although only a trend - in
other words, potentially a fluke - the higher death rate "raises important
questions". Look hard
enough and doubts emerge even over this trend. For example, Kathleen Fahy,
professor of midwifery at the At yesterday's
conference, Fahy used these and other flaws to attack the credibility of the
Cochrane review and argued strongly that RCTs were ill-suited to measure
birth-centre outcomes. Given that we have some research evidence, why is the
picture still so hazy? Denis Walsh,
one of the four Britain-based authors of the review, who is on a 10-month
sabbatical in In other words,
if there are about two baby deaths for every 1000 of the low-risk women who use
birth centres, you need to sample a vast number of women to catch enough cases
unlucky enough to have a baby die. "Some
experts have suggested a sample of 300,000 may be required to compare perinatal
mortality by place of birth," Walsh says. Pesce claims
there's only a one in 20 chance that the Cochrane review finding of a higher
death rate was a fluke, and "if there had been a seventh [trial], that
would probably have created statistical significance". Maybe. Perhaps we'll have to wait a bit
longer; Sally Tracy, associate professor of midwifery practice development at
the University of Technology, Sydney, is awaiting publication of a study she
has painstakingly pulled together, looking at the outcomes from all 1,001,249
women who gave birth in Australia between 1999 and 2002, including 21,800 who
did so in midwife centres (although not stand-alone). "The results will
blow the critics away," | |||||||||||||||
