Haematology and Pregnancy

Question 1

What happens to Hb levels in the blood during pregnancy?

Answer 1

• Non-pregnant state lower limit = ~120g/L.
• During pregnancy, this declines to 110→105→100 g/L as the lower limit during pregnancy.
• Due to small increase in RBCs but massive increase in plasma.

Question 2

What happens to WBC count during pregnancy?

Answer 2

Increased number of WBCs. Mainly neutrophils.

Question 3

What happens to coagulability of blood during pregnancy?

Answer 3

• Pregnancy = hypercoagulable state.​
• Increase in fibrinogen and factors VIII, Ix and X.
• Decreased activity of antithrombin III which normally inhibits coagulation.
• Good because it reduces risk of haemorrhage at delivery.
• Bad because it increases risk of VTE.

Question 4

Describe the mechanism of anaemia in pregnancy.

Answer 4

• Irregular menstruation can cause borderline iron deficiency going into pregnancy.
• The increased demands of the foetus can then tip the scales to cause iron deficiency anaemia.
  
  • Check ferritin (MCV may be ‘normal’).
• It is common to supplement iron during pregnancy but constipation / abdominal pain / nausea are common.
  
  • IV iron (Ferrinject) is an option.
  • IM very painful and oral is poorly tolerated.

Question 5

What is the leading direct cause of thromboembolic disease.

Answer 5

Pulmonary embolism

Question 6

When are women at high risk of thromboembolic disease?

What are the additional risk factors?

Answer 6

• Pregnancy and 6 weeks post-partum is a high-risk, hypercoagulable state.
• Additional risk factors:
  
  • Age
  • Previous clot
  • Smoking
  • Twins
  • Obesity
  • Thrombophilia (e.g. anti-thrombin deficiency)

Question 7

How is thromboembolic disease treated during pregnancy?

Answer 7

• LMWH.
• Increased rate of clearance and volume of distribution requires bd dose (normally once daily).
• Patient will need prophylactic anticoagulation in future pregnancies.

Question 8

What are the components of pre-eclampsia?

Answer 8

• Hypertension
• Fluid retention
• Proteinuria
• Headache
• High urate (blood marker)

Question 9

What is HELLP syndrome?

What is the treatment?

Answer 9

• A minority of patients with pre-eclampsia will develop HELLP:
  
  • Haemolysis
  • Elevated liver enzymes (ALT/AST)
  • Low platelets
• Treatment:
  
  • Prompt delivery of baby
  • Supportive care

Question 10

Describe disseminated intravascular coagulation (DIC).

What is the treatment?

Answer 10

• Small blood clots develop throughout the bloodstream through fibrin deposition and deposition of platelet plugs within vessels via systemic activation of the coagulation cascade, blocking small blood vessels.
• The increased clotting depletes the platelets and clotting factors needed to control bleeding, causing excessive bleeding.
• Linked with obstetric disasters – placental abruption, amniotic fluid embolism, dead foetus.
• Treatment:
  
  • Treating the cause
  • Administering coagulation factors and platelets

Question 11

What are the risk factors for a major ante- or post- partum haemorrhage?

Answer 11

• Placenta praevia
• Placental abruption
• Retained products of conception
• Poor uterine contraction after delivery
• Important to recognise excessive blood loss. Treat the cause and replace RBCs / platelets / coagulation factors.

Question 12

Describe the monitoring of a foetus from a mother with significant red cell antibodies.

Answer 12

• Several ways to monitor:
  
  • Flow in middle cerebral artery
  • Ascites
  • Liver and spleen size
• Umbilical cord sampling for blood count / blood group and antibody level.

Question 13

Describe the neonatal management of a Rh+ baby of Rh- mother.

Answer 13

• Clinical assessment.
• Blood count and reticulocytes / group / red cell antibodies / bilirubin / direct Coombes test looking for membrane-bound antibody.
• Allow antibodies to decline.
• Phototherapy to increase bilirubin conjugation.
• Top-up or exchange transfusion.