1 anaemia n tcp in pregnancy 2008 dr g kidson

8/3/2019 1 Anaemia n TCP in Pregnancy 2008 Dr G Kidson

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Anaemia &

Thrombocytopenia inPregnancy

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 < 110g/L

T2 Hb < 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 < 50g/L)

Foetal (esp < 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

pregnancyLow MCV Normal MCV High MCV

Iron deficiency Iron deficiency Folate

deficiencyThalassaemia Chronic disease B12 deficiency

Sickle cell

Haemolysis

Bleeding

Infection


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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

Formulation Elemental Fe(mg)

Folic Acid(mcg)

Ferrous sulfate 105 -

Fefol 87.4 300

FGF 80 300

Elevit 60 800

BlackmoresPregnancy

5 200


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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 tissuestores 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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HaemoglobinopathiesGenotype Anaemia MCV Spleen Transfusion

Thalassaemia (2 genes)

Trait +,, 1 abnormal gene None-mild N/ +/- No

Intermedia +, + 2 mildly

abnormal genes

Mild-moderate + Sometimes

Major , 2 abnormal genes Severe + Dependent

Thalassaemia (4 genes)

Trait , 1 missing gene None N - No

2-gene minus ,

,

2 missing genes None-mild N/ +/- No

HbH disease , 3 missing genes Mod - severe + Sometimes

Barts disease , 4 missing genes Incompatible with lifedeath in utero

Sickle Cell (2 genes)

Trait s, 1 abnormal gene None N - No

Disease s, s 2 abnormal genes Mod-severe N/ +/-/ Variable

thal compound s, /+ 2 abnormal genes Variable +/-/ Variable


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Screening

Why? - Detect foetus at risk of majorhaemoglobinopathy

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:1. MCV may notdetect - thalassaemia trait

- sickle trait2. Hb may not detect- thalassaemia trait

- thalassaemia trait- sickle trait

Iron deficiency must be excluded as cause oflow MCV


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HbEPG: Hb Electrophoresis

Separates different haemoglobins according to charge

Alkaline & acid gels

Known position of haemoglobin bands

Control

HbE trait

HbE disease

HbS trait

thalassaemiatrait

Normal

HbA

HbF

HbS

HbA2,C,E


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HPLC: High Performance Liquid

Chromatography Separate according to elution time

Quantify % of different haemoglobins present

Iron deficiency lowers HbA2

Normal

HbA predominanthaemoglobin: 88%

HbS trait

HbS band:39%

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 accessedwhen 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 haemoglobinopathyscreening 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 - < 50 x 109/L


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Causes of Thrombocytopenia in

Pregnancy Pregnancy-specific

Increased destruction:

Gestational

Preeclampsia

HELLP

Acute Fatty Liver ofPregnancy

Disseminated intravascular

coagulopathy

Non-pregnancy-specific


Idiopathic thrombocytopenic purpura(ITP)

Microangiopathies: TTP, HUS, DIC

SLE, Antiphospholipid syndrome

Drug-induced

Viral infections: HIV, HCV, EBV, CMV

HypersplenismDecreased production:

Bone Marrow Disease

Nutritional deficiency

Liver disease

Congenital thrombocytopenia


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Gestational

Preeclampsia

HELLP



coagulopathy






Drug-induced



Bone Marrow Disease


Liver disease



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Gestational

Preeclampsia

HELLP



coagulopathy






Drug-induced



Bone Marrow Disease


Liver disease



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Gestational

Preeclampsia

HELLP



coagulopathy






Drug-induced



Bone Marrow Disease


Liver disease



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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 ordestruction 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

Mildthrombocytopenia: Platelet count > 70 x109/L (usually > 100)

Anti-platelet antibodies do not reliablydistinguish 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


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Idiopathic Thrombocytopenic

Purpura (ITP) Maternal haemorrhage riskincreased,

relates to platelet count Platelet count < 20: risk of spontaneous bleeding

Platelet count > 50: aim for NVD Platelet count > 70: for epidural (variable, anaesthetist preference)

Foetal thrombocytopeniadue to trans-placental passage of maternal IgG: 10-20% platelet count < 50 x109/L

5% platelet count < 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


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Thank-you

1 anaemia n tcp in pregnancy 2008 dr g kidson

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