Maternal Medicine - Endocrine, Haematology

Question 1

What happens to:

TBG
Total T4 and T3
Free T4
TSH
in pregnancy

Answer 1

TBG - increased
Total T4 and T3 - no change
TSH - slight fall in first trimester

Question 2

How many pregnancies are affected by hyperthyroidism and what proportion have a FHx of autoimmune disease/are due to Graves’ disease?

Answer 2

1 in 500
50% have FHx
90% due to Graves’

Question 3

What is the mortality rate of a thyroid crisis (‘storm’)

Answer 3

25%

Question 4

What is the rate of preterm labour in hyperthyroidism?

Answer 4

11-25%

Question 5

What is the rate of stillbirth in hyperthyroidism?

Answer 5

8-15%

Question 6

What is the rate of neonatal thyrotoxicosis in hyperthyroidism?

Answer 6

1-10%, usually transient

Most common if active disease in third trimester

Question 7

How many pregnancies are complicated by hypothyroidism?

Answer 7

1%

Background 0.5% overt
2.5% subclinical

Question 8

How many women with postpartum thyroiditis will develop hypothyroidism within 4 years?

Answer 8

20-30%

Question 9

How many women with macroadenomas will have enlargement in pregnancy?

Answer 9

15%

Question 10

How long after radioactive iodine should pregnancy be delayed?

Answer 10

6/12

Question 11

What is the preferred medical treatment of hyperthyroidism in pregnancy?

Answer 11

PTU in T1 - lower teratogenicity

Consider change to carbimazole in T2 as ?PTU related hepatotoxicity in offspring

Question 12

What is the recommendation with thyroxine dosing in pregnancy?

Answer 12

Increase by 25mcg when pregnancy confirmed
Monitor 4-6 weekly
Maintain TSH <2.5
Change to pre pregnancy dose post partum and check levels 4-6/52

Question 13

What is the background risk of being a carrier for Haemophilia?

Answer 13

1 in 20,000

Question 14

What is the % of population had Von Willerbrands?

Answer 14

1%

Question 15

Which is the most common inherited bleeding disorder

Answer 15

Von willerbrands
1% of population
Chromosome 12 abnormality

Question 16

What’s the role of vWF?

Answer 16

Stabilises factor VIII and helps platelets adhere to injured vessels
( factor 8 part of intrinsic pathway. 8a aides 9a’s conversion of 10 to 10a which changed prothrombin to thrombin.

Question 17

What is type 1 vWD?

Answer 17

Most common (75%)
Autosomal dominant 
Quantitative deficiency
Normal vWF

Question 18

Describe the different forms of type 2 vWD?

Answer 18

Autosomal dominant occasionally recessive
Qualitative deficiency
Abnormal vWF
2a low platelet function, no high molecular multimers
2b platelet increased affinity for Gp1b
2m low platelet function
2n normal platelet function.reduced factor 8 binding
(All but 2n have abnormal platelet function but normal factor 8 binding)

Question 19

What is type 3 vWD?

Answer 19

Auto recessive

Negligible vWF and reduced function of factor 8

Question 20

What happens to vWF and factor 8 levels in pregnancy ?

Answer 20

Increase
All increase apart from
factor 2 and protein C unchanged
Factors 11 and S decrease

Question 21

How do you diagnose vWD?

Answer 21

FBC- low platelets in type 2b, anaemia if bleeding
Clotting screen- APTT may be prolonged/ normal
VWF antigen - amount vWF present
VWF ristocetin-function of vWF
Factor 8 levels- may be low in all types
Collagen binding assay
Factor 8 binding -reduced in 2n
Rostocetin induced platelet agglutination- (RIPA) increased in 2b
Multimer analysis- none in 2a, normal or large in 2m

Question 22

What is the Management of vWF ante tally?

Answer 22

Joint Obstetric/haematology care
Von willerbrand screen 1st and third trimester
Anaesthetic review
vWF activity and factor 8 levels > 50 before invasive testing