Haematology in Pregnancy

Question 1

What are the FBC changes in pregnancy?

Answer 1

Mild anaemia
Macrocytosis
Neutrophilia
Thrombocytopenia - increase platelet size

Question 2

What causes the mild anaemia in pregnancy?

Answer 2

Red cell mass rises (120-130%)
Plasma volume rises (150%)
Results in net dilution

Question 3

How does the iron requirement change in pregnancy?

Answer 3

Increases
300mg for foetus
500mg for maternal increased red cell mass
Increase in daily iron absorption in gut (1-2 - 6mg)

Question 4

What happens to folate requirement in pregnancy?

Answer 4

Increases
Growth and cell division
Approximately additional 200mcg/day

Question 5

What are the complications of iron deficiency in pregnancy?

Answer 5

IUGR
Prematurity
Postpartum haemorrhage

Question 6

What is the recommended advice for folic acid supplementation?

Answer 6

Supplement before conception and for >12 weeks gestation

Dose 400ug/day

Question 7

What is considered anaemia at different stages of pregnancy?

Answer 7

1st trimester Hb<110g/l
2nd/3rd trimster Hb<105g/L
postpartum Hb<100g/l

Question 8

What is the platelet change in pregnancy?

Answer 8

Falls, increase in size
Non pregnant: 225-249 x10^9/L
Pregnant: 175-199x10^9/L

Question 9

What are some pathological causes of thrombocytopenia in pregnancy?

Answer 9

Pre-eclampsia
Immune thrombocytopenia (ITP)
Microangiopathic syndromes
All other causes: bone marrow failure, leukaemia, hypersplenism, DIC etc

Question 10

What are the platelet requirements for delivery?

Answer 10

• >50x10^9/l sufficient for delivery (>70 for epidural)

Question 11

When does platelet count being to rise post partum?

Answer 11

D2-5

Question 12

What are the features of thrombocytopenia in preeclampsia?

Answer 12

50% pre-eclampsia get thrombocytopenia
Probably due to increased activation and consumption
Associated with coagulation activation
Usually remits following delivery

Question 13

What are the treatment options for immune thrombocytopenia in pregnancy?

Answer 13

IV immunoglobulin

Steroids

Question 14

How may the baby be affected by ITP in pregnancy?

Answer 14

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

Question 15

What would be avoided in women with ITP due to the risk of low platelets in the foetus?

Answer 15

Instrumental delivery

Invasive monitoring

Question 16

What characterises the microangiopathic syndromes in pregnancy?

Answer 16

Microangiopathic haemolytic anaemia (MAHA)
Deposition of platelets in small blood vessels
Thrombocytopenia
Fragmentation and destruction of rbc within vasculature
Organ damage (kidney, CNA, placenta)

Question 17

What changes occur to coagulation factors in pregnancy?

Answer 17

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

Question 18

What is the net effect of coagulation changes in pregnancy?

Answer 18

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

Question 19

What is the leading cause of maternal mortality?

Answer 19

VTE

Question 20

What is the incidence of thrombosis in pregnancy?

Answer 20

1 per 1000 <35 years

2 per 1000 >35 years

Question 21

What thrombosis related investigations can be used in pregnancy?

Answer 21

Doppler and VQ are safe to perform in pregnancy

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

Question 22

What additional factors may increase the risk of VTE in pregnancy?

Answer 22

Hyperemesis/dehydration
Bed rest
Obesity
Pre-eclampsia
Operative delivery
Previous thrombosis
Age
Parity
Multiple pregnancy
IVF - ovarian hyperstimulation

Question 23

What is used for prevention of thromboembolic disease in pregnancy?

Answer 23

Women with risk factors should receive prophylactic heparin + TED stockings
Mobilise early
Maintain hydration

Question 24

What is the treatment of thromboembolic disease in pregnancy?

Answer 24

LMWH as for non-pregnant (does not cross the placenta)
After 1st trimester monitor anti Xa
Stop for labour of planned delivery, especially for epidural

Question 25

What drug to treat thromboembolic disease cannot be used in pregnancy

Answer 25

Warfarin - crosses placenta

Question 26

What can occur giving warfarin in first trimester?

Answer 26

``` Chondrodysplasia puncta Abnormal cartilage and bone formation Early fusion of epiphyses Nasal hypoplasia Short stature Asplenia Deafness Seizures ```

Question 27

What obstetric complications can be associated with antiphospholipid sydndrome?

Answer 27

Recurrent miscarriage Three or more consecutive miscarriages before 10 weeks gestation, one or more morphologiacally normal foetal loss after 10th week of gestation, one or more preterm births before 34th week of gestation owing to placental disease

Question 28

What are the most common causes of fatal bleeding in pregnancy?

Answer 28

Placenta praevia | Placenta accreta

Question 29

What defines post partum haemorrhage?

Answer 29

>500ml blood loss

Question 30

What are the mechanisms of post partum haemorrhage?

Answer 30

Major factors: uterine atony, trauma Haematological factors minor except: dilutional coagulopathy after resuscitation, DIC in abruption, amniotic fluid embolism etc

Question 31

What factors can precipitate disseminated Intravascular Coagulation?

Answer 31

``` Amniotic fluid embolism Abruptio placentae Retained dead foetus Preeclampsia (severe) Sepsis ```

Question 32

What are the options if there is suspected haemoglobinopathy of the foetus?

Answer 32

Proceed Prenatal diagnosis: CVS sampling 10-12 weeks, amniocentesis 15-17 weeks, fetal blood sampling Ultrasound for hydrops

Question 33

What are the FBC results for iron deficiency?

Answer 33

``` Hb: normal or decreased MCH: low (in proportion to Hb) MCHC: low RDW: increased RBC: low or normla Electrophoresis: normal ```

Question 34

What are the FBC results for thalassaemia trait?

Answer 34

``` Hb: normal MCH: lower for same Hb MCHC: relatively preserved RDW: normal RBC: increased Hb electrophoresis: HbA2 increased in beta-thal trait, normal in alpha-thal trait ```