VTE in pregnancy

Question 1

Overall incidence of PE in pregnancy and puerperium

Answer 1

1-2 per 1000
1.3 per 10,000 antenatally

Question 2

Increase in risk of VTE in pregnnacy and postpartum

Answer 2

4-6 fold increase
21-84 fold increase compared to non-preg, 5 fold pregnant rate

Question 3

Treatment dose tinzaparin

Answer 3

175units/kg

Question 4

Treatment dose dalteparin

Answer 4

<50kg: 5000units BD
50-69kg: 6000units BD
70-89kg: 8000units BD
90-109kg: 10,000units BD
110-125kg: 12,000 units BD
>125kg = d/w haem
OD dosing double BD dose

Question 5

Increased risk of VTE if BMI >30

Answer 5

PE: OR = 14.9
DVT: OR = 4.4

Question 6

Increased risk of VTE whilst in hospital

Answer 6

18 fold increase

Question 7

Increased risk of VTE when discharged from hospital

Answer 7

6 fold higher for 28 days

Question 8

Risk of VTE in IVF pregnancy
Overall
1st trimester

Answer 8

Overall: 2x higher
T1: VTE 4x higher, PE 7x higher

Question 9

Recurrence rate of VTE in pregnancy

Answer 9

11% during pregnancy
3% post pregnancy

Question 10

Thromboprophylaxis if single previous VTE

Answer 10

At least post-partum LMWH

Question 11

Anti-thrombin deficiency and previous VTE tx

Answer 11

High risk of recurrence
Give higher dose LMWH (up to tx dose) and continue until 6/52 PP or PO anticoag restarted

Consider anti-Xa monitoring (target 0.5 – 1.0 iu/ml at 4 hours post-dose) and anti-thrombin replacement at initiation of labour or prior to CS

Question 12

APS and previous VTE - risk and management

Answer 12

High risk of recurrence
Give higher dose LMWH (up to tx dose) and continue until 6/52 PP or PO anticoag restarted

Question 13

High risk thrombophilias
What are they?
Management

Answer 13

Antithrombin deficiency
Protein C or S deficiency
Compound or homozygous for low-risk thrombophilia

Consider antenatal LMWH
Recommend post-partum LMWH for 6 weeks
Use standard prophylactic dose except anti-thrombin deficiency where intermediate dose may be required

Question 14

Lower risk thrombophilias
What are they?
Management?

Answer 14

Heterozygous for factor V Leiden or prothrombin G20210A mutations
Antiphospholipid antibodies

Counts as 1x minor VTE risk factorM

Question 15

Major VTE risk factors postnatal

Answer 15

Any previous VTE
Anyone requiring antenatal LMWH
High-risk thrombophilia (antithrombin deficiency, protein C or S deficiency, compound or homozygous for low-risk thrombophilia)
Low-risk thrombophilia (heterozygous for factor V Leiden or prothrombin G20210A mutations, antiphospholipid antibodies) + FHx of VTE

Tx = 6 weeks LMWH

Question 16

Intermediate risk factors postnatal

Answer 16

Caesarean section in labour
BMI >/= 40 kg/m2
Re-admission or prolonged admission (>/= 3 days)
Any surgical procedure except immediate perineal repair
Medical comorbidities

Tx = 10 days postnatal

Question 17

Risk of VTE post CS

Answer 17

ELCS: 2x SVB
EMCS: 4x SVB