Hi there,

Thanks for clarifying this Rachel.  I think you point is absolutely right.  And although I have not explained myself very well, this was my point.  It is my understanding that the pie chart is indeed a fare reflection of the obesity numbers/proportions for the population as a whole (we are talking general population here. I confess I have not looked into these very closely, so please correct me if I am wrong as I am largely relying on the figures highlighted in the D of H 2010 Healthy lives, healthy people: our strategy for public health in England, White paper).

What I was trying to suggest was that if obesity were overrepresented in the stillbirth figures represented in my pie chart, then this would imply an increased risk or at least a possible association risk.  But as you rightly point out, this is not in fact the case, which to my logic at least, suggests no increased risk or association.  Granted this is very raw data but I think it raises some important questions, not least why do this already vulnerable group of women sustain higher section rates?

thanks again



Mandie Scamell 
________________________
From: Rachel Rowe [[log in to unmask]]
Sent: 07 February 2012 14:15
To: Scamell, Amanda
Subject: FW: Fetal monitoring and obesity

Hi Mandie
I'm not sure that your pie chart shows what you think it might, at least, if I understand you (and it) correctly.  I assume that it shows the percentage of stillbirths by BMI group.  In itself this doesn't tell you anything as it doesn't show you the percentage of each BMI group in the population.  You would expect the majority of stillbirths to come from the 'normal' BMI group since that is where the majority of births are - most women are of 'normal' BMI.
My understanding of the CMACE data is that it is fairly unequivocal that there is an increased risk of stillbirth with increasing BMI.  According to the report, 8.6 per 1000 live births in the >35 group compared with 3.9 per 1000 in all births.  Unless I'm missing something...

Best wishes
Rachel


Rachel Rowe
Health Services Researcher
National Perinatal Epidemiology Unit
University of Oxford
Old Road Campus
Oxford
OX3 7LF

Tel: 01865 289713
Fax: 01865 289701
[log in to unmask]
http://www.npeu.ox.ac.uk/


-----Original Message-----
From: A forum for discussion on midwifery and reproductive health research. [mailto:[log in to unmask]] On Behalf Of Scamell, Amanda
Sent: 07 February 2012 13:29
To: [log in to unmask]
Subject: Re: Fetal monitoring and obesity

what an excellent question, I look forward with anticipation to the debate around this.

Especially since I have recently been pulling out (and rounding up incidentally) the latest CEMACE figures on this issue for the purposes of a lecture on the inverse care law in maternity care.  Granted this is very blunt tool but that aside, if the measure used to ask this question is mortality measured in terms of stillbirth then these figures suggest the answer to the question is, no (I've attached very basic EXCEL pie if anyone is interested in having a look).

It seems to me that the figures presented by CEMACE pretty much represent population incident rates of obesity (forgive me if I'm wrong on that understanding) suggesting there is no increased risk of stillbirth for obese women.  An interesting thought, especially in relation to choices during birth, not least place of birth, without any other associated and confounding risk factors.  (This observation is not to trivialise the inverse care law incidentally, but rather to correctly direct the associations involved in it, which appear to continue to be poverty and ethnicity rather than life style issues which can be 'blamed' upon the individuals involved.  Sadly, I believe this is pretty much what J.Hart said back in 1971 and is certainly corroborated by the Black report)

Thank you Belinda for raising this interesting issue.

Mandie Scamell
________________________________________
From: A forum for discussion on midwifery and reproductive health research. [[log in to unmask]] On Behalf Of Belinda Cox [[log in to unmask]]
Sent: 07 February 2012 11:13
To: [log in to unmask]
Subject: Fetal monitoring and obesity

Dear all,

We are discussing the issue around continuous fetal monitoring with a mother whom has a raised BMI (>35). Is there any evidence that suggests high BMI is an independent risk factor for poor fetal outcomes where there is no co morbidity?

What are you all doing in practice?

Thanks :-)

Belinda