Exactly Andrea. There is an article in the Journal
of Nurse-Midwifery (now the Journal of Midwifery and Women's Health)
Volume 39, No.2 (Supplement), March/April 1994, pp.133 - 148 "
Nurse-Midwifery Management of iron-deficiency anaemia during
pregnancy" by Janet L.Engstrom, CNM, Ph.D and Claudia P. Sittler,
CNM, MS which discusses these issues and is excellent reading. It gives you
an algorithm for a differential diagnosis and pathophysiology of the
various anemias and the beneficial and normal haemodilution of the healthy
second trimester (no pathophysiology here). I have a photocopy of this article
and could send copies by snail mail to anyone who wants, though I am sure you
can find this journal in some Uni library.
marilyn
----- Original Message -----
Sent: Tuesday, September 21, 2004 6:30
PM
Subject: [ozmidwifery] measuring Hb
during pregnancy
All this talk about haemaglobin reminded me about something I
read recently and thought would make a good discussion.
I have just
finished reading Michel O'Dent's book 'The Casarean' ( available from Birth
International) which was very interesting reading. In it he discusses
measuring Hb during pregnancy and I will type the relevent section from pages
115-116
He states that '... there is
a widespread belief that this test can effectively detect anaemia and iron
deficiency. In fact this test cannot diagnose iron deficiency because the
blood volume of pregnant women is supposed to increase dramatically, so the
haemoglobin concentration indicates first the degree of blood dilution, an
effect of placental activity. A large british study, involving more than
150,000 pregnancies found the highest average birth weight was in the group of
women who had a haemaglobin concentration between 8.5 and 9.5. Furthermore
when the haemaglobin concentration fails to fall below 10.5 there is an
increased risk of low birth weight, pre term birth and pre-eclampsia. The
regrettable consequence of routine evaluation of haemoglobin is that all over
the world, millions of pregnant women are wrongly told that they are anaemic
and are given iron supplements. there is a tendency both to overlook the side
effects of iron (constipation, diarhhoea, heartburn etc) and to forget that
iron inhibits the absorption of such an important growth factor as zinc.
Furthermore, iron is an oxidative substance that can exacerbate the production
of free radicals and might even increase the risk of pre-eclampsia. ' /color> of course he gives references
Well I knew the first
bit about blood dilution but was not aware of the study that showed the higher
birth weight amongst the women with lower Hb or the tendancy to pre eclampsia
to women with higher Hb. Makes sense though that if there is higher blood
pressure then placental function/flow will be decreased and lead to lower
foetal growth. Makes the whole thing a bit of a joke though doesnt it as Hb is
the one thing I thought was worth knowing of the battery of tests that women
are subjected to. Maybe we should be celebrating when there Hb comes back
lower that 10.5 and 'worrying' when it doesn't. Cant you see it now new
indication for keeping an eye on BP "Hb above 10.5'. Food for thought though.
As it will make any though of supplements virtually obsolete.
Andrea
Quanchi
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