Obstetric Haematology

Question 1

What are the key changes to FBC that occur in pregnancy?

Answer 1

Mild anaemia (RBC rise but plasma volume rises more, causing net RBC dilution)

Macrocytosis

High neutrophils (neutrophiia)

Thrombocytopoenia (low platelets)

Question 2

Why does macrocytosis occur in pregnancy?

Answer 2

Could be physiological, or due to folate/B12 deficiency

Question 3

Why does thrombocytopenia occur?

Answer 3

Increased platelet size

Platelet count falls

Question 4

What are the iron demands in pregnancy for foetus/mother?

Answer 4

Foetus = 300mg 
Mother = 500mg

Question 5

What is recommended daily intake of iron in pregnancy?

Answer 5

60mg

Question 6

What is the increase in iron absorption in pregnancy=

Answer 6

From 2mg to 6mg

Question 7

Why does iron absorption need to be very tightly regulated?

Answer 7

Because once it is absorbed, there is no way to get rid of it

Question 8

What is folate needed for in pregnancy?

Answer 8

For cell growth and division

Reduces risk of neural tube defects

Question 9

How much additional folate is required in pregnancy?

Answer 9

200mcg/day

Question 10

What does iron deficiency cause?

Answer 10

IUGR

Question 11

What is the recommended dose of folate in pregnancy? When should it be started?

Answer 11

Start before conception

Take for 12 weeks prior to gestation

Question 12

What iron supplementation is required in pregnancy?

Answer 12

None- done on a one to one basis

Question 13

What are the two main causes of microcytic anaemia in pregnancy?

Answer 13

Iron deficiency

Thalassaemia

Question 14

If you start iron replacement, how long should you keep going for?

Answer 14

3 months

Until all RBC have regenerated

Question 15

When in pregnancy does platelet count drop? By how much?

Answer 15

First trimester

By 10%

Question 16

What change in platelet structure occurs during pregnancy?

Answer 16

Larger platelets are produced

Question 17

What are pathological causes of thrombocytopenia in pregnancy?

Answer 17

Pre-eclampsia
ITP
Microangiopathic syndromes
All other non-pregnant causes

Question 18

What does a VERY LOW platelet count tell us about the cause?

Answer 18

The lower the platelet count, the more likely it is pathological

Question 19

What occurs to coagulation in pregnancy?

Answer 19

HYPERCOAGUABLE STATE

Question 20

What is the leading cause of maternal death in UK?

Answer 20

VTE

Question 21

Which leg is more likely to be affected by VTE in pregnancy?

Answer 21

LEFT

Due to uterine compression of the left iliac vein

Question 22

When is the highest incidence of pregnancy related VTE?

Answer 22

6 weeks post partum

Question 23

What are 2 key risk factors in pregnancy related VTE

Answer 23

Obesity

C sec

Question 24

What are the three key systems in place to control bleeding from the placental site?

Answer 24

Hypercoaguability
Hypofibrinolytic state
Uterine contraction

Question 25

When are the two key significant time periods for death from PE?

Answer 25

AFTER birth (40-46)

First trimester

Question 26

What are investigations for PE in pregnancy=

Answer 26

Dopples US

VQ scan

Question 27

Is D dimer useful for PE in pregnancy?

Answer 27

No because it is elevated in pregnancy regardless

Question 28

Is D dimer useful in PE in general?

Answer 28

It has high specificity (good at FALSE NEGATIVE)

It has low sensitivity (BAD at true positives)

Question 29

How is Vichrows triad affected in pregnancy?

Answer 29

Stasis - reduced vessel return, due to compression of uterus affecting flow

Hypercoagulability - due to increased blood coag

Endothelial wall injury - vessel anatomy changes during pregnancy

Question 30

At what age does VTE risk increase significantly?

Answer 30

Over 35

Question 31

How can you prevent VTE in pregnancy?

Answer 31

Prophylactic heparin + stockings
(LMWH if high risk)
Mobilise early
Maintain hydration

Question 32

How do you treat VTE in pregnancy?

Answer 32

LMWH

Question 33

Can you give warfarin in pregnancy?

Answer 33

NO it is teratogenic and crosses the placenta

Question 34

What time frame must you stop heparin if you want to give an epidural?

Answer 34

24 h if treatment dose of heparin

12 h if prophylactic dose of heparin

Question 35

What are 2 requirements for antiphopholipid syndrome?

Answer 35

Recurrent miscarriage

Antibodies (lupus, anticardiolopin)

Question 36

What treatment increases live birth rates in APS=?

Answer 36

aspirin + heparin

Question 37

What is a fatal consequence of an amniotic fluid embolism?

Answer 37

DIC

Question 38

What haemoglobinopathies do we screen for?

Answer 38

Alpha / Beta thalassaeia

Sickle cell

Question 39

How do you identify alpha thalassaemia?

Answer 39

Molecular dx

HPLC (high performance liquid chromatography) is NOT enough