Anaemia

Question 1

Anaemia in pregnancy - overview

Answer 1

1. Low Hb concentrations are a part of normal pregnancy - plasma volume increases by about 1.2L, causing a dilutional anaemia despite an associated increase in red cell mass. Hb levels fall from early pregnancy, reaching a nadir at 36 weeks (20-25g/L below pre-pregnancy ranges)
2. Hb

Question 2

Anaemia in pregnancy - clinical features

Answer 2

1. Fatigue
2. Dyspnoea
3. Palpitations
   Note - the above are common symptoms of normal pregnancy

When Hb reaches 60-70g/L, the mother is at risk of:
4. High-output cardiac failure
5. Extreme fatigue
At these levels, the fetus is at the lower limit of adequate oxygenation

Question 3

Anaemia in pregnancy - ix

Answer 3

1. FBE (Hb concentration, platelet and WBC counts) + blood film

Microcytic anaemia

2. Serum ferritin concentration
3. Haemoglobin electrophoresis (identifying carrier states of haemoglobinopathies if serum ferritin normal)

Macrocytic anaemia

4. Erythrocyte and serum folate levels (reduced in folate deficiency)
5. Note - serum B12 levels are difficult to interpret in pregnancy and are commonly physiologically low in the second half of gestation

Question 4

Anaemia in pregnancy - ix/dx for main types (3)

Answer 4

1. Iron deficiency anaemia
   - Low MCV, low MCHC, low ferritin
2. Folate deficiency
   - High MCV, low serum and red cell folate levels
3. Vitamin B12 anaemia
   - Uncommon to make new dx in pregnancy; serum B12 levels difficult to interpret in pregnancy (?)

Question 5

Iron deficiency anaemia in pregnancy - overview and mx

Answer 5

1. Fetus requires 280mg of iron and a further 400-500mg is required for expansion of maternal red cell mass. If iron intake does not meet increased requirements, iron deficiency +/- anaemia can occur
2. In women eating an adequate diet, the decrease in Hb is rarely significant enough to cause a serious clinical problem. RF for iron deficiency = vegetarians, multiple pregnancy, hx iron deficiency or menorrhagia, low socioeconomic status (consider prophylactic supplements in these women)
3. Oral iron = ferrous sulfate 300mg. Contains 60mg of elemental iron (iron available for absorption), of which only 10% actually gets absorbed
4. If oral iron ineffective or not tolerated, parenteral iron may be required, e.g. IV iron sucrose
5. Side effects of iron supplementation = upper GI discomfort and constipation