Haemotology in Pregnancy Flashcards
What is the composition of blood?
2/3 Plasma
1/3 RBC’s
What happens to blood volume during pregnancy?
Increases by 1.5L
Plasma volume increased
Red cell mass decreases
Overall Hb decreases
What happens to RBC volume between weeks 0-10?
Dips then rises after 10 weeks
When does Hb fall to lowest in pregnancy?
32-34 weeks
What anaemia develops in pregnancy?
Physiological/dilutional anaemia MCV slightly increased MCH normally unchanged Hb < 104 Ferritin < 15
What is polycythaemia?
Increased Hb
How is iron stored?
Most contained in Haemoglobin
Excess stored as
1) Ferritin in Liver
2) Haemosiderin in bone marrow
What are normal ferritin levels?
> 15ug/L
What can cause ferritin levels to increase?
Inflammation
Acute phase protein
How is iron deficiency treated?
1st or 2nd trimester: oral Fe replacement
3rd trimester: IV iron
What clinical conditions increase hepcidin levels?
CKD RBC transfusions Fe administration Replete Fe stores Genetic factors Infectious/inflam disorders
What clinical conditions decrease hepcidin levels?
Ineffective erythropoiesis Hypoxia/anaemia CLD Alcohol abuse HCV Genetic factors Testosterone
Who is B12 deficiency seen in?
Vegan/veggie
Pernicious anaemia
Post bariatric surgery
What happens to serum B12 in pregnancy?
Falls
If true deficiency - homocysteine increases
What are the risk factors for folic acid deficiency?
Hyperemesis
Twin preg
What happens with WBC count in pregnancy?
Increases - mainly neutrophils
Lymphocyte count decreases
What is thrombocytopenia?
Low platelets due to reduced production and increased consumption
< 115
What are the differential diagnosis of thromocytopenia?
- Immune thrombocytopenia
- Familial thrombocytopenia
- Drugs
- Pseudothrombocytopenia
- Bone marrow infiltration
- Hypersplenism
What happens in bone marrow failure?
- Aplastic anaemia - due to reduced production
- Leucopenia - too few WBC’s
- Thrombocytopenia
- Pancytopenia
What causes increased consumption of platelets out of pregnancy?
- Immune
- Sepsis
- Massve haemorrhage
- Cardiac bypass surgery
- Hypersplenism
What causes increased consumption of platelets in pregnancy?
- HELLP: haemolysis, elevated liver enzymes, low platelets
- Gestational thrombocytopenia
- TTP
- Disseminated intravascular coagulation: massive haemorrhage, amniotic fluid embolism
What should you consider with low MCV?
Thalassaemia trait
But Fe deficiency anaemia most likely
Why is there an increased risk of venous thromboembolism during pregnancy?
1) Stasis - venous, compression of left common iliac vein
2) Vessel wall injury
3) Hypercoagulability - increases pro-coagulant, reduced anticoagulant, reduced fibrinolysis
What causes compression of left common iliac vein in pregnancy?
As uterus grows
= venous stasis = deep vein thrombosis
What are antenatal risk factors for VTE in pregnancy?
- Previous DVT/PE
- Antiphospholipid syndrome
- Myeloproliferative disorder
- Sickle cell disease
- Systemic lupus erythematosis
- Obesity
