Haem: Obstetric Haematology Pt.1

Question 1

What haematological changes are seen on FBC in pregnancy?

Answer 1

• Mild anaemia (DILUTION)
  
  • Red cell mass rises (120-130%)
  • Plasma volume rises (150%)
• Macrocytosis
  
  • Normal
  • Folate or B12 deficiency
• Neutrophilia
• Thrombocytopenia
  
  • Increased platelet size

Question 2

What are the 3 Hb thresholds for anaemia in pregnancy?

Answer 2

<110 in 1st trimester

<105 in 2nd/ 3rd trimester

<100 post partum

Question 3

What are the increased demands required in pregnancy?

Answer 3

• Iron requirement
  
  • 300mg for fetus
  • 500mg for maternal increased red cell mass
• Folate requirements increase
  
  • Growth and cell division
  • Approx additional 200mcg/day required

Question 4

How iron deficiency diagnosed?
What is the treatment for iron deficiency in pregnancy?

Answer 4

FBC: Low Hb, MCV < 80

200 mg ferrous sulfate daily for 3 months

Question 5

What does iron deficiency during pregnancy increase risk of?

Answer 5

IUGR

Prematurity

Postpartum haemorrhage

Question 6

What is normal iron absorption per day?

What is iron absorption during pregnancy?

Answer 6

Normal absorption 1-2mg a day.

This increases to 6mg during pregnancy.

Question 7

Why is iron absorption increased during pregnancy?

Answer 7

Hepcidin decreases and ferroportin levels increase. This results in increased iron absorption.

Question 8

What are the RCOG recommendation for daily folate intake?

Answer 8

400 mcg daily

Question 9

What does folate deficiency increase risk of during pregnancy?

Answer 9

Neural tube defects

Question 10

What is the cut off level of platelets required for:

1. Epidural anaethesia
2. Delivery

Answer 10

1. > 70 x10^⁹/L
2. > 50 x10^⁹/L

Higher for epidural due to serious risk of spinal haematoma

Question 11

What are causes of thrombocytopenia in pregnancy?

Answer 11

• Physiological:
  
  • ‘gestational’ / incidental thrombocytopenia
• Pre-eclampsia
• Immune thrombocytopenia (ITP)
• Microangiopathic syndromes
• All other causes: bone marrow failure, leukaemia, hypersplenism, DIC etc.

Question 12

What is the most commone cause of thrombocytopaenia <150x10⁹/L in pregnancy?

Answer 12

Gestational thrombocytopenia

Question 13

What is the most common cause of thrombocytopaenia <100x10⁹/L in pregnancy?

Answer 13

ITP and pre-eclampsia

This suggests something pathological is occurring.

Question 14

What is gestational thrombocytopenia?

Answer 14

A physiological decrease in platelet count of about 10% during pregnancy
Does not affect foetus.

Question 15

What is the underlying mechanism of gestational thrombocytopenia?

Answer 15

Mechanism poorly defined.

Possibly due to dilution and increased consumption.

Question 16

When does platelet count increase following gestational thrombocytopenia?

Answer 16

Platelet count rises around 2-5 days after delivery

Question 17

When does platelet count fall most during pregnancy in gestational thrombocytopenia?

Answer 17

Most of the fallen platelet count occurs in 3rd trimester

Question 18

What percent of women with preeclampsia get thrombocytopenia?

Answer 18

50%

Thrombocytopenia is proportionate to severity of preeclampsia.

Question 19

What causes thrombocytopenia in preeclampsia?

Answer 19

Increased activation and consumption of platelets due endothelial injury

Question 20

What percentage of thrombocytopenia during pregnancy is accounted for by immune thrombocytopenia (ITP)?

Answer 20

5% of thrombocytopenia in pregnancy

• TP may precede pregnancy
• Early onset

Question 21

What are the treatment options for ITP in pregnancy?

Answer 21

• IVIG (FIRST LINE)
• Steroids (not ideal as lots of side effects)