Haematological/immunological changes in pregnancy

Question 1

• As trophoblast invades decidua-

Answer 1

• increase in uterine Natural Killer (NK) cells and dendritic cells- allow re-modelling of uterine wall rather than cytotoxic or antigen presenting function. Macrophages prominent too.
• very infrequent lymphatic channels, minimal lymphoid tissue

Question 2

Physiological changes in pregnancy

Answer 2

• RBC decline
• White blood cell numbers rise
• Fall in platelets
• rise in MCV
• Rise in fibrinogen and factors VIII, IX, X so hyper coagulable state

Question 3

Anaemia in pregnancy

Answer 3

• Increased demands of foetus iron def anaemia
- check ferritin (MCV may be “normal”)
• Common to supplement iron in pregnancy but constipation/abdo pain/nausea common- IV iron eg Ferinject is an option

Question 4

folic acid in pregnancy

Answer 4

educe neural tube defects (neural tube formed in 2-4 weeks from conception)

Question 5

Immune thrombocytopenic purpura (ITP)

Answer 5

purple rash

• is an autoimmune disease of children and adults
• may be triggered by infection, drug or pregnancy -auto antibodies to platelets (marrow normal)
• treated by watch and wait/ steroids/ immunoglobulins/ splenectomy/ drugs to mimic thrombopoetin
• may need treatment to achieve platelets of 50+ for labour
• some risk of neonatal thrombocytopenia due to IgG antibodies crossing placenta

Question 6

Thrombotic thrombocytopenic purpura (TTP)

Answer 6

• Rare but life-threatening “thrombotic microangiopathy”
• Enzyme (ADAMS13) prevents large Von Willebrands polymers- this becomes
deficient and platelets aggregate • Presents as fever, neurological
and renal disease, low platelets
and fragmented red cells. Coagulation screen usually normal

Question 7

how would you treat Thrombotic thrombocytopenic purpura (TTP)

Answer 7

• Can be associated with auto-immune disease/HIV/pregnancy

* Treated by plasma exchange (to replace enzyme

Question 8

when Is high risk of death in pregnancy - pulmonary embolism

Answer 8

during the pregnancy and 6 weeks postpartum

Question 9

what are additional risk factors for birth complications

Answer 9

• previous clot -smoking -twins -obesity

- thrombophilia eg anti-thrombin deficiency

Question 10

Thromboembolic disease

Answer 10

• In late pregnancy, pelvic veins compressed (L>R) leg swelling
• Progressive pain, tenderness, unilateral swelling- ?DVT
• Doppler exam of leg
• Chest X ray- if abnormal then CT pulmonary angiogram (higher radiation dose) more reliable than ventilation/perfusion scan

Question 11

how would you treat Thromboembolic disease

Answer 11

• Low molecular weight heparin (LMWH) is treatment of choice
• Increase rate of clearance and volume of distribution requires twice
daily dose
• Monitoring of anti Xa levels (3-4 hours post dose) required to show effective dosing
• Will need prophylactic anticoagulation in future pregnancies

Question 12

Pre-eclampsia (PET)

Answer 12

hypertension, fluid retention, proteinuria, headache, urate high • A minority of patients with PET will develop HELLP

Question 13

HELLP syndrome

Answer 13

evidence of
haemolysis- anaemia
-red cell fragments
- raided LDH
also, raised liver enzymes (ALT/AST), low platelets

Question 14

treatment for both PET and HELLP

Answer 14

Treatment- prompt delivery of baby and supportive care

Question 15

Disseminated intravascular coagulation (DIC)

Answer 15

• Acute and serious complication typically following- -placental abruption
-amniotic fluid embolism
-dead foetus
Typically haemorrhagic, very unwell, organ failures, depletion of coag factors, low platelets, red cell fragments

Question 16

What is the treatment for Disseminated intravascular coagulation (DIC)

Answer 16

treating the cause, coagulation factors and platelets

Question 17

risk factors for major haemorrhage

Answer 17

placenta praevia (over cervix)
-placental abruption
-retained products of conception
- poor uterine contraction after delivery
Important to recognise excessive blood loss- treat the cause and replace red cell/platelets/coagulation factors

Question 18

Screening criteria- Wilson and Jungner-1

Answer 18

• Recognisable latent or early symptomatic stage
• A simple test with high sensitivity and specificity
• This test should be acceptable to the population
• Early effective treatment needs to be of clear benefit • Agreement as to who should be treated

Question 19

• Haemoglobin needs -

Answer 19

• Hb A (adult) = 2 alpha, 2 beta
• Hb A2= 2 alpha, 2 delta
• Hb F (foetal)= 2 alpha, 2 gamma

Question 20

Detection of haemoglobinopathy/thal carriers

Answer 20

• Abnormal haemoglobins will show on electrophoresis/HPLC