----- Original Message -----
Sent: Thursday, September 23, 2004 5:04
AM
Subject: Re: [ozmidwifery] measuring Hb
during pregnancy
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. '
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
