Obstetric Haematology Flashcards

1
Q

FBC abnormalities in pregnancy

A

Mild anaemia
Macrocytosis
Neutrophilia
Thrombocytopenia

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2
Q

Cause of macrocytosis in pregnancy

A

Normal (physiological)

Folate or B12 deficiency

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3
Q

Why does mild anaemia occur in pregnancy

A

Red cell mass rises (120-130%)

Plasma volume rises (150%)

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4
Q

What are the increased iron requirements in pregnancy

A

300mg for the foetus
500mg for the maternal increased red cell mass

RDA: 30mg
Increase in adily iron absorption: 1-2mg to 6mg

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5
Q

What requirements increase in pregnancy

A

Iron

Folate

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6
Q

Why are folate requirements increased in pregnancy

A

Growth and cell division

Approximately additional 200mcg/day required

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7
Q

What can iron deficiency cause in pregnancy

A

IUGR
Prematurity
Postpartum haemorrhage

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8
Q

What are the iron and folate supplements recommended by WHO for pregnancy

A

WHO recommended 60mg iron + 400mcg folic acid daily during pregnancy

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9
Q

What is routinely supplemented in pregnancy

A

Folic acid

Iron is not routinely supplemented in the UK

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10
Q

Why is folic acid supplements recommended in pregnancy

A

Advice reduces risk of neural tube defects
Supplement before conception and for >12 weeks gestation
Dose of 400ug/day

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11
Q

What happens to the platelet count in pregnancy

A

Platelet count falls in pregnancy

Non-pregnancy: 225-249
Pregnancy 175-199

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12
Q

Causes of thrombocytopenia in pregnancy

A

Physiological - gestational/incidental thrombocytopenia
Pre-eclampsia
Immune thrombocytopenia (ITP)
Microangiopathic syndromes
All other causes: BM failure, leukaemia, hypersplenism, DIC, etc…

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13
Q

Most common cause of thrombocytopenia with platelets <150 in pregnancy

A

Gestational

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14
Q

Most common cause of thrombocytopenia with platelets <100 in pregnancy

A

Gestational

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15
Q

Most common cause of thrombocytopenia with platelets <70 in pregnancy

A

ITP and pre-eclampsia

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16
Q

What is gestational thrombocytopenia

A

Physiological decrease in platelet count ~ 10%
>50x109/l sufficient for delivery (>70 for epidural)
Mechanism poorly defined: Dilution + increased consumption
Baby not affected
Platelet count rises day 2 – 5 post delivery

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17
Q

Why does pre-eclampsia cause thrombocytopeina in pregnancy

A

50% get thrombocytopenia - proportionate to severity
Probably due to increased activation and consumption
Association with coagulation activation
Usually remits following delivery

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18
Q

Features of immune thromboycytopenia in pregnancy

A

5% of thrombocytopenia in pregnancy - may precede pregnancy, early onset
Baby may be affected

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19
Q

Treatment options for ITP in pregnancy

A

IVIG
Steroids, etc…
Anti-D where RhD +ve

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20
Q

Features of ITP effects on baby

A
Unpredictable (platelets <20 in 5%)
Check cord blood and then daily 
May fall for 5 days after delivery 
Bleeding in 25% of severely affected (IVIG if low) 
Usually normal delivery
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21
Q

What are the features of microangiopathic haemolytic anaemia (MAHA)

A

Deposition of platelets in small blood vessels
Thrombocytopenia
Fragmentation and destruction of rbc within vasculature
Organ damage (kidney, CNS, placenta)

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22
Q

What are some MAHA syndromes

A

Pre-eclampsia
HELLP
TTP
HUS

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23
Q

What are the coagulation changes in pregnancy

A
Factor VIII and vWF increase 3-5 fold 
Fibrinogen increases 2 fold 
Factor VII increases 0.5 fold 
Protein S falls to half basal 
PAI-1 increases 5 fold 
PAI-2 produced by placenta increase 5 fold 

A hypercoagulale and hypofibrinolytic state

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24
Q

Why is haemorrhage at pregnancy a risk

A

Pregnancy causes a hypercoagulable and hypofibrinolytic state

Rapid control of bleeding from placenta site essential at time of delivery (700ml/min blood loss)

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25
Q

What are the features of the procoagulant state in pregnancy

A

Increased thrombin generation
Increased fibrin cleavage
Reduced fibrinolysis
Interact with other maternal factors

26
Q

What can occur due to the pro-coagulation state in pregnancy

A

Increased rate of thrombosis: PE, DVT

27
Q

When in pregnancy is the greatest risk of death from PE

A

1st and 2nd trimesters, but risk continues into the post-partum period (6 weeks post-delivery)

28
Q

What are the risk factors for PE in pregnancy

A
BMI >25 
Personal/family history for VTE
Air travel 
Hyperemesis gravidarum 
Ovarian hyperstimulaton syndrome 
Unrelated surgery
29
Q

What are the investigations carried out for suspected PE in pregnancy

A

Doppler and VQ are safe to perform in pregnancy

D-dimer often elevated in pregnancy - not useful for exclusion of thrombosis

30
Q

What factors increase the risk of thrombosis in pregnancy

A
Changes in blood coagulation 
Reduced venous return - approximately 85% are left DVT
Vessel wall changes 
Hyperemesis/dehydration
Bed rest 
Obesity - BMI>29 x 3 risk of PE
Operative delivery 
Previous thrombosis/thrombophilia 
Age 
Parity 
Multiple pregnancy 
Other medical problems: HbSS, nephrotic syndrome 
IVF: ovarian hyperstimulation
31
Q

What are some symptoms of PE to be vigilant of in early pregnancy

A

Chest pain
Shortness of breath
Leg pain

32
Q

What diagnostic tests can be done for PE in pregnancy

A

VQ
CXR
Venogram
CTPA

33
Q

What is the treatment for suspected PE in pregnancy

A

Thromboprophylaxis in at risk groups

Therapy should be given pending the results of further testing

34
Q

How can thromboembolic disease be prevented in pregnancy

A

Women with risk factors should receive prophylactic heparin + TED stockings: either throughout pregnancy, or in peri post partum period, highest risk get adjusted dose of LMWH
Mobilise early
Maintain hydration

35
Q

How are high risk of PE pregnant women managed

A

Required antenatal prophylaxis with LMWH

Continue at least 6 weeks postnatal prophylaxis

36
Q

How are intermediate risk of PE pregnant women managed

A

Consider antenatal prophylaxis with LMWH

Continue at least 10 days postnatal prophylaxis

37
Q

How is a PE in a pregnant women with three risk factors managed

A

Prophylaxis with LMWH from 28 weeks

38
Q

When giving treatment for PE/prophylaxis, what is the management plan

A

LMWH as for non-pregnant women - does not cross the placenta. Give 1 or 2/day
DO NOT GIVE WARFARIN (crosses placenta)
After 1st trimester monitor anti-Xa (4 hour post 0.5-1.0u/ml)
Stop treatment for labour of planned delivery, especially for epidural…Epidural: wait 24 hours after treatment dose, 12hours after prophylactic dose

39
Q

Why is thrombophilia in pregnancy associated with pregnancy complications

A

An increasde tendency to thrombosis is associated with impaired placental circulation

40
Q

What are the complications of thrombophilia in pregnancy

A
IUGR
Recurrent miscarriage 
Late foetal loss 
Abruptio placentae
Severe PET
41
Q

What is antiphospholipid syndrome

A

Thrombophilia associated with pregnancy complications.

Recurrent miscarriage + persistent lupus anticoagulant (LA)/ anticardiolipin antibodies (ACL)

42
Q

What increases the likelihood of antiphospholipid syndrome

A

Adverse pregnancy outcome: three or more consecutive miscarriages before 10 weeks of gestation
One or more morphologically normal fetal losses after the 10th week of gestation
One or more preterm births before the 34th week of gestation owing to placental disease.

43
Q

Beyond antiphospholipid syndrome, what other thrombophilias may be associated with pregnancy complications

A

AT, PC, PS deficiency
Factor V leiden
Hyperhomocysteinemia

44
Q

What are the causes of post-partum haemorrhage

A

Placenta praevia

Placenta accreta

45
Q

What is the principle reason for hysterectomy

A

Post partum haemorrhage

46
Q

Define post-partum haemorrhage

A

> 500ml blood loss

5% of pregnancies have blood loss >1L at delivery

47
Q

Major risk factors for post-partum haemorrhage

A

Uterine atony
Trauma
Haematological factors are usually minor, except: dilutional coagulopathy after resuscitation, DIC in abruption, amniotic fluid embolism

48
Q

DIC in pregnancy

A

Coagulation changes in pregnancy predispose to DIC

49
Q

What can precipitate DIC in pregnancy

A
Amniotic fluid embolism 
Abruptio placentae 
Retained dead foetus 
Pre-eclampsia (if severe)
Sepsis
50
Q

Features of amniotic fluid embolism

A

1 in 20000-30000 births
Sudden onset shivers, vomiting, shock. DIC
86% mortality
Presumed due to Tissue Factor in amniotic fluid
Almost all >25 years old
Usually third trimester
No association with parity

51
Q

Symptoms of amniotic fluid embolism

A

Sudden onset shivers, vomiting, shock. DIC

52
Q

Aims of haemoglobinopathy screening in pregnancy

A

To avoid birth of children with:
Alpha-thalassaemia (death in utero, hydrops fetalis)
Beta-thalassaemia (transfusion dependent)
HbSS - life expectancy 43 years
Other compound HbS syndromes - symptomatic, stroke, etc…
Some compound thalassaemias - transfusion dependent, iron overload

53
Q

NHS sickle cell and thalassaemia screening programme features

A

In high prevalence areas
Family origin questionnaire
FBC: MCH
HPLC

54
Q

Ethnicities important in alpha-thalassaemia trait

A

Far east
SE Asia
Greece
Turkey

55
Q

Haemoglobinopathy counselling for thalassaemias

A

Important disorders are all recessive
Therefore if mother is heterozygous partner should be tested.
Combinations as important as homozygous states

56
Q

What are the options following screening for haemoglobinopathies

A
Proceed
Prenatal diagnosis@
CVS sampling (10-12 weeks)
Amniocentesis (15-17 weeks), fetal blood sampling 
Ultrasound screening for hydrops
57
Q

Features of sickle cell disease in pregnancy

A

Hb SS (sickle cell anaemia),
HbS/clinically abnormal Hb e.g. HbC; βthal
~100 pregnancies/year in SCD females in UK
Vaso-occlusive crises become more frequent
Anaemia and existing chronic diseases exaggerated

58
Q

Complications of sickle cell disease in pregnancy

A

Foetal growth restriction
Miscarriage, preterm labour, pre-eclampsia
Venous thrombosis

59
Q

Management of sickle cell disease in pregnancy

A

Red cell transfusion (top up or exchange)
Prophylactic transfusion: reduced number of vaso-occlusive episodes, not clear whether affects foetal or maternal outcome
Alloimmunisation - extended phenotype RhD, E, Kell

60
Q
Normal or low Hb
Low MCH (proportionate to Hb)
Low MCHC
Raised RDW
Low or normal RBC
Hb electrophoresis normal
A

Iron deficiency

61
Q
Normal (rarely low) Hb
Low MCH 
Relatively preserved MCHC
Normal RDW
Increased RBC
Hb electrophoresis HbA2 raised in beta-thalassaemia, normal in alpha-thalassaemia trait
A

Thalassaemia trait

62
Q

What is neonatal alloimmune thrombocytopenia and haemolytic disease of the newborn

A

Maternal immune response against foetal antigens requiring monitoring and intervention during pregnancy