Anaemia in Pregnancy Flashcards
What is the WHO definition of anaemia in pregnancy?
Hb of
What physiological changes in pregnancy can contribute to anaemia?
- Increase in maternal plasma volume by up to 50% (peak of haemodilution at 32 weeks)- Iron stores utilised by fetus
What are the 3 major mechanisms of developing anaemia?
- Decreased intake or absorption2. Depressed production3. Increased demand or loss
What is the most common cause of anaemia?
Iron deficiency
List 6 causes of anaemia
- Iron deficiency2. Folate deficiency3. Vitamin B12 deficiency4. Haemoglobinopathies (e.g. thalassaemia, sickle-cell disease)5. Haemolytic anaemia6. Bone marrow aplasia
Major mechanisms of iron deficiency anaemia in pregnancy?
- Expansion of maternal red cell mass- Use of iron stores by fetus and placenta
Daily iron requirements in females of reproductive age?
2mg/day
Daily iron requirements in early pregnancy?
4mg/day
Daily iron requirements in late pregnancy (32 weeks)?
6-8mg/day
Which dietary group are at particular risk of developing an iron deficiency anaemia and why?
Vegans. Haem iron, derived from meat, is more readily absorbed than non-haem iron
How much blood loss can be tolerated on average without a drop in Hb level?
1000ml
Why is decreased MCV of RBCs following a microcytic anaemia often not obvious in pregnancy?
Decreased MCV may be masked by the relatively large proportion of young, large RBCs (increased erythropoeisis)
- What is the earliest abnormal laboratory test in iron deficiency anaemia in pregnancy? - What does this test reflect?- What aspect of the test bolsters it’s reliability?
- Serum ferritin levels. - Is an indirect reflection of total body iron stores.- It is not affected by recent ingestion of iron, thus giving a reliable long-term representation of iron levels
- What is the most reliable method of diagnosing iron deficiency anaemia in pregnancy? - Why isn’t this done often? - When is it done?
- Bone marrow biopsy to measure iron levels there- Highly invasive technique- Used when non-invasive tests are not conclusive and a differential is crucial
Management of iron deficiency anaemia of pregnancy
- Identify and treat underlying cause e.g. diet, infection- Look for and treat associated infections e.g. UTI, GIT parasites- Oral iron supplements (ferrous sulphate) –> NB adherence
When is blood transfusion for anaemia considered?
- Very severe anaemia- Especially considered in women who are near to term (36 weeks+)
How to prevent iron deficiency anaemia
All antenatal patients should receive 200mg ferrous sulphate orally, daily
Why is folate an essential micronutrient?
Required for cell growth and division (essential for DNA and amino acid synthesis through THF production)
Potential consequences of folate deficiency for the mother?
- Megaloblastic anaemia- Glossitis- Diarrhoea- Depression
Factors which increase the risk of folate deficiency anaemia?
- Multiple pregnancy- Excessive alcohol consumption- Anti-convulsant medications, and other folate antagonists- Grand multiparity with short intervals between pregnancies
Main aspects of laboratory diagnosis of folate deficiency anaemia?
- Macrocytosis- On peripheral smear: oval macrocytes; hypersegmented neutrophil nuclei- Low reticulocyte count- RBC folate levels more accurate measure than serum levels
Alterations in laboratory parameters in iron deficiency anaemia?
- Decreased Hb (relatively late development)- Microcytosis (may be masked by erythropoeisis)- Decreased MCH- Decreased MCHC- Increased total iron-binding capacity- Decreased serum ferritin- Increased zinc protoporphyrin (= Hb with zinc in centre of molecule, rather than iron)- Increased transferring receptor levels- Decreased bone marrow iron levels
Management of folate deficiency anaemia in pregnancy?
Oral folic acid supplements (5mg daily)
Risk factors for Vitamin B12 deficiency anaemia in pregnancy?
- Vit B12 deficiency very rarely causes megaloblastic anaemia in pregnancy- Dietary deficiency possible in strict vegans- Decreased absorption in patients with pernicious anaemia or following gastric resection
Management of Vitamin B12 deficiency in pregnancy
- Recommended intake 3ug/day in pregnancy- Empiric therapy usually given if this diagnosis is suspected [neuro findings e.g. numbness, paraethesia, ataxia, altered mental state] - Parenteral route (GIT absorption often the cause)
Dr Jansen’s causes of anaemia in pregnancy (9)
- Dilutional effect (physiological)- Iron deficiency- Blood loss- Haemolysis- Folate/B12 deficiency- Chronic disease- Infection (e.g. malaria)- Haemoglobinopathy- Cancers
