Pernicious Anaemia Society
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Advice please

I was diagnosed with pernicious anaemia last year and had a long battle with my doctors to get adequate treatment but now due to my insisting on blood tests for my 15 year old daughter who was also showing signs she has been diagnosed with it as well and she was due to start injections today but the doctor has delayed them because he said her iron is to low and wants her to take iron tablets for a few more weeks before staring b12 injections, is this right

Thank you in advance for any help 

6 Replies

Hi maxfogarty,

Delaying the start of the b12 treatment for your daughter's P.A. sounds stupid to me.

I'm not a medically qualified person but I regularly became iron anaemic in the 1970s & 80s upwards of ten years after my own P.A. diagnosis & b12 treatment started.

After a visit to a haematologist I was told I needed to be on iron permanently so I can see absolutely no reason why your daughter can't have both b12 and iron at the same time.

I hope your daughter's doctor gets to see sense and starts the b12 quickly.



I can't answer your question but I would suggest contacting the PAS who might know if its standard practice to delay b12 injections if iron is low.

pernicious-anaemia-society.... 01656 769 717

Office open from 8am till 2pm every day except Sundays. May take a couple of days to get a reply to a phone message.

My understanding is that iron, b12 and folate work together so good levels of all are needed.

Has she had her folate levels checked? And a full blood count (FBC)?

High MCV and high MCH on a FBC can indicate the possibility of macrocytosis (enlarged red blood cells). Low B12 and/or low folate can lead to macrocytosis. Low iron can lead to microcytosis (small red blood cells). A person with both low B12 (and/or low folate) and low iron may have a normal range MCV on a FBC because the effect of the low iron masks the effect of the low B12 (and/or low folate).

A blood smear aka blood film may show both macrocytis and microcytic cells in the same sample of someone with both conditions.

Pleased to hear that they listened to you and seem willing to help your daughter.

I am not a medic just a patient who has struggled to get a diagnosis.


It also sounds stupid to me.  the BCSH guidelines are not to delay treatment if there are neurological symptoms because of the risk of permanent damage.  Taking B12 is not going to have an adverse effect on her iron levels - infact may help but ...


Agree. It's stupid.


Yeah this is exactly right.  Delaying b12 while the iron levels come up - which can easily take 3 months - could or more likely will cause nerve damage if the b12 is low enough.  

Its possible the doctor is looking to do a regression, which is to say they want to test the variables in isolation to see if improving one improves them all.  The hypothesis is that the iron levels are the underlying cause of the pernicious anemia.  

That misunderstands the problem, though.  A lack of b12 will cause anemia as will a lack of iron, but b12 deficiency will also directly cause nerve damage.  B12 absorption won't interfere with iron absorption.  There is simply no harm in b12 supplementation at maintenance levels, period. 

1 like

Apart from what Sleepybunny says about macro and microcytosis there's no reason at all to delay B12 injections and many reason not to delay them.

It's possible for PA to cause both B12 and iron deficiency as the autoimmune gastric atrophy that causes a lack of Intrinsic Factor (IF - required for absorption of B12) can also cause a lack of hydrochloric acid in the stomach - required for proper absorption of iron.


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