Anaemia

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Anaemia Thrombocytopenia in Pregnancy

• Giselle Kidson-Gerber
• Haematology Registrar
• Prince of Wales Hospital

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Anaemia in pregnancy
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Physiological changes in normal pregnancy

• RBC dilution with rise in blood volume and plasma
  volume
• Definition of anaemia in pregnancy
• T1, T3 Hb lt 110g/L
• T2 Hb lt 105g/L
• Return to normal within 1 week post-partum, if
  normal iron stores

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Potential consequences of moderate to severe
anaemia

• Maternal
• Fatigue, dyspnoea, syncope, chest pain
• Mortality (esp lt 50g/L)
• Foetal (esp lt 60g/L)
• Impaired mental development if low iron stores
• Low birth weight
• Preterm labour
• Perinatal death
• Low amniotic fluid volume
• Spontaneous miscarriage
• Placental Hypertrophy

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Common causes of anaemia in pregnancy
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Preconception

• Assess nutrition status
• Full blood count
• Investigate if anaemia present
• Correct anaemia prior to conception
• Haemoglobinopathy screening

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Investigations

• FBC, with MCV, blood film
• Fe studies ferritin esp.
• Folate (RCF stores) B12 levels
• Reticulocyte count
• UEC, LFT, Coagulation studies
• Haemoglobinopathy screening

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Iron deficiency anaemia

• Most common cause in Western countries
• Increased iron requirements during pregnancy,
• especially multiple pregnancies
• Replace Ferrous sulfate 325mg tds (105mg
  elemental Fe)
• Anaemia corrects in 4 - 6 weeks
• Stores replaced in 4 - 6 months
• Dietary advice
• Once replete
• Ongoing supplement 30 - 60mg elemental iron
  daily
• Monitor, including whilst breastfeeding

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Iron therapies
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Folic Acid deficiency

• 2nd most common cause of anaemia in pregnancy
• Increased requirements for mother and foetus
• Red cell folate measure more reflective of
  tissue stores over past months
• Supplement all 200 - 500mcg/d
• (greater if haemolysis)
• Replacement 1000mcg/d

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Haemoglobinopathies Practical significance

• Major haemoglobinopathy in mother
• Rare
• Specialist obstetric haematology care
• Haemoglobinopathy traits in mother
• Silent risk foetus
• Transfusion-dependent anaemia or sickle cell
  disease
• Barts disease/hydrops foetalis maternal foetal
  morbidity
• Dependent on maternal and paternal genotype
• Importance of appropriate timely screening

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Difficulties with detection of haemoglobinopathy
traits

• Patient asymptomatic
• Patient unaware of carrier status
• Difficult to detect in laboratory
• May have normal Hb or MCV
• Haemoglobinopathy screening does not
  detect all cases
• Iron deficiency can mask indicator of
  thalassaemia trait

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Haemoglobinopathies
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Screening

• Why? - Detect foetus at risk of major
  haemoglobinopathy
• Who? - At risk ethnic groups, ? all
• (Southern Europe, Middle East, Africa, Asia,
  Indian subcontinent)
• - Mother partner
• When? - Ideally preconception
• - Limited timeframe for Ix intervention
• What? - FBC Hb, MCV
• - HbEPG (includes HPLC, HbH bodies)

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Full blood count

• Simple
• Limitations
• ? MCV may not detect - a thalassaemia trait
  - sickle trait
• ? Hb may not detect - ß thalassaemia trait
• - a thalassaemia trait - sickle
  trait
• Iron deficiency must be excluded as cause of low
  MCV

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HbEPG Hb Electrophoresis

• Separates different haemoglobins according to
  charge
• Alkaline acid gels
• Known position of haemoglobin bands

HbF
HbA
HbS
HbA2,C,E
HbS trait
Control
Normal
ß thalassaemia trait
HbE trait
HbE disease
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HPLC High Performance Liquid Chromatography

• Separate according to elution time
• Quantify of different haemoglobins present
• Iron deficiency lowers HbA2

Normal
HbS trait
HbS band 39
HbA predominant haemoglobin 88
HbA 50
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When to refer or ask for help

• Positive result
• Unexplained anaemia
• Uncertain what investigations to perform
• Uncertain how to interpret investigations
• Complex area!
• Variation in conditions and test results
• Specialist services are available DNA testing
  is readily available should be accessed when
  there is doubt

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DNA testing

• Confirm results or clarify unclear results
• Test mother partner
• Foetus
• If have a known mutation in both parents
• Usually gives definitive genotype, although not
  100 predictive of phenotype
• Formal genetic counselling prior
• Must be organised EARLY in pregnancy
• - ideally preconception.
• Option of prenatal genetic diagnosis with IVF

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Take home message

• Evaluate anaemia PRIOR to pregnancy
• Determine cause of low MCV
• Replace iron, if deficient
• Low threshold for haemoglobinopathy screening and
  referral

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Thrombocytopenia in pregnancy
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Thrombocytopenia

• Physiological thrombocytopenia in normal
  pregnancy
• Average decrease in platelet count of 10
• Occurs mostly in 3rd trimester
• Due to haemodilution or accelerated destruction
• Normalises 24 -72 hours post-partum
• Complicated Thrombocytopenia
• Up to 10 of pregnancies
• Mild - 100 - 150 x 109/L
• Moderate - 50 - 100 x 109/L
• Severe - lt 50 x 109/L

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Causes of Thrombocytopenia in Pregnancy

• Pregnancy-specific
• Increased destruction
• Gestational
• Preeclampsia
• HELLP
• Acute Fatty Liver of Pregnancy
• Disseminated intravascular coagulopathy

• Non-pregnancy-specific
• Increased destruction
• Idiopathic thrombocytopenic purpura (ITP)
• Microangiopathies TTP, HUS, DIC
• SLE, Antiphospholipid syndrome
• Drug-induced
• Viral infections HIV, HCV, EBV, CMV
• Hypersplenism
• Decreased production
• Bone Marrow Disease
• Nutritional deficiency
• Liver disease
• Congenital thrombocytopenia

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Causes of Thrombocytopenia in Pregnancy

• Pregnancy-specific
• Increased destruction
• Gestational
• Preeclampsia
• HELLP
• Acute Fatty Liver of Pregnancy
• Disseminated intravascular coagulopathy

• Non-pregnancy-specific
• Increased destruction
• Idiopathic thrombocytopenic purpura (ITP)
• Microangiopathies TTP, HUS, DIC
• SLE, Antiphospholipid syndrome
• Drug-induced
• Viral infections HIV, HCV, EBV, CMV
• Hypersplenism
• Decreased production
• Bone Marrow Disease
• Nutritional deficiency
• Liver disease
• Congenital thrombocytopenia

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Causes of Thrombocytopenia in Pregnancy

• Pregnancy-specific
• Increased destruction
• Gestational
• Preeclampsia
• HELLP
• Acute Fatty Liver of Pregnancy
• Disseminated intravascular coagulopathy

• Non-pregnancy-specific
• Increased destruction
• Idiopathic thrombocytopenic purpura (ITP)
• Microangiopathies TTP, HUS, DIC
• SLE, Antiphospholipid syndrome
• Drug-induced
• Viral infections HIV, HCV, EBV, CMV
• Hypersplenism
• Decreased production
• Bone Marrow Disease
• Nutritional deficiency
• Liver disease
• Congenital thrombocytopenia

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Causes of Thrombocytopenia in Pregnancy

• Pregnancy-specific
• Increased destruction
• Gestational
• Preeclampsia
• HELLP
• Acute Fatty Liver of Pregnancy
• Disseminated intravascular coagulopathy

• Non-pregnancy-specific
• Increased destruction
• Idiopathic thrombocytopenic purpura (ITP)
• Microangiopathies TTP, HUS, DIC
• SLE, Antiphospholipid syndrome
• Drug-induced
• Viral infections HIV, HCV, EBV, CMV
• Hypersplenism
• Decreased production
• Bone Marrow Disease
• Nutritional deficiency
• Liver disease
• Congenital thrombocytopenia

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Clinical approach

• Symptoms, bleeding history
• Prenatal platelet count
• Gestation
• Previous pregnancies
• Associated features
• Co-morbidities

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Gestational Thrombocytopenia

• Occurs in 5-8 of all pregnancies
• 75 of all pregnancy-associated thrombocytopenia
• ? Mechanism haemodilution, accelerated plt
  turnover, trapping or destruction at placenta
• Maternal haemorrhage risk not increased
• Foetal thrombocytopenia risk not increased

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Gestational Thrombocytopenia

• Clinically - asymptomatic
• - normal pre-natal platelet count
• - occurs in late T2 in T3
• - normalises post-partum
• Mild thrombocytopenia
• Platelet count gt 70 x109/L (usually gt 100)
• Anti-platelet antibodies do not reliably
  distinguish from ITP
• Diagnosis of exclusion

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Idiopathic Thrombocytopenic Purpura (ITP)

• 5 of pregnancy-associated thrombocytopenia, 0.1
  of pregnancies
• Concern maternal and foetal haemorrhage
• Clinically - any trimester
• - prenatal thrombocytopenia
• - bleeding history
• Especially likely to be ITP if
• Platelet count lt50 x109/L
• T1
• History of auto-immune disease

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Idiopathic Thrombocytopenic Purpura (ITP)

• Maternal haemorrhage risk increased,
• relates to platelet count
• Platelet count lt 20 risk of spontaneous bleeding
• Platelet count gt 50 aim for NVD
• Platelet count gt 70 for epidural (variable,
  anaesthetist preference)
• Foetal thrombocytopenia
• due to trans-placental passage of maternal
  IgG
• 10-20 platelet count lt 50 x109/L
• 5 platelet count lt 20 x109/L 25-50 develop
  bleeding
• Best predictor sibling
• Check cord platelet count at delivery, nadir day
  2-3.
• Therapeutic options monitor only, IVIg,
  prednisone, (splenectomy)

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Summary of approach to thrombocytopenia in
pregnancy

• Exclude pre-eclampsia syndromes
• BP, UA, symptoms, FBC, UEC, LFT, Uric Acid
• Exclude non-pregnancy-related medical causes,
  usually have specialist involved already
• When to refer
• Known history of ITP
• Unknown cause platelet count is
• lt130 x 109/L in T1 T2
• lt100 x 109/L in T3
• Otherwise monitor FBC monthly

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• Thank-you