Antenatal screening for VTE

Question 1

How do you decide if pt warrants LMWH antenatally?

Answer 1

• Screen all women
• Re assess risk if admitted or if they develop other problems
• 4 risk factors or more need LMWH + 6/52 after
• 3 risk factors - LMWH from 28 weeks + 6/52 after
• 2 risk factors - 10/7 days LMWH post natally only

Question 2

What is the risk of VTE in thrombophilia?

Answer 2

20-50% of VTE are in patients with thrombophilia

Question 3

What % of obese people died of PE?

Answer 3

60%

Question 4

VTE and admission to hospital

Answer 4

18-fold increase risk of first VTE during admission
6-fold increase risk up to 28 days post discharge
Higher in the 3rd trimester and women >35
4-fold higher for 3 days

Question 5

What is the risk of VTE if previous VTE?

Answer 5

2-11%

Question 6

When would you tell a woman about warfarin?

Answer 6

• Ideally stop prior to pregnancy
• Stop Within 2 weeks from finding out to be pregnant, at least before 6 weeks
• Can be re started 5-7 days post delivery
• Can breastfeed on it
• 5% fetus exposed between 6-12 weeks will have malformations; higher incidence if on >5mg warfarin/day

Question 7

Women with VTE associated with either antithrombin deficiency or APS or with recurrent VTE

Answer 7

Should be offered thromboprophylaxis with higher
dose LMWH (either 50%, 75% or full treatment) antenatally and for 6 weeks

Question 8

Women in whom the original VTE was unprovoked/idiopathic or related to estrogen (estrogencontaining contraception/pregnancy) or related to a transient risk factor

Answer 8

Should be offered thromboprophylaxis with LMWH throughout the antenatal period.

Question 9

In women in whom the original VTE was provoked by major surgery from which they have recovered and who have no other risk factors

Answer 9

LMWH can be withheld antenatally until 28 weeks provided no additional risk factors are present.

Question 10

Testing for thrombophilia in women with prior VTE

Answer 10

• Women with a family history of VTE and either antithrombin deficiency or where the specific thrombophilia has not been detected should be tested for antithrombin deficiency.
• Women with an unprovoked VTE should be tested for the presence of antiphospholipid antibodies.

Question 11

Asymptomatic heritable thrombophilia

Answer 11

• Women with asymptomatic antithrombin, protein C or S deficiency or those with more than one thrombophilic defect (including homozygous factor V Leiden, homozygous prothrombin gene mutation and compound heterozygotes) need LMWH antenatally and postnatally
• Heterozygosity for factor V Leiden or prothrombin gene mutation or antiphospholipid antibodies are considered as risk factors for thrombosis in asymptomatic women (1 risk factor/2 risk factors/3 risk factors).
• Women with no personal history or risk factors for VTE but who have a family history of an unprovoked or estrogen-provoked VTE in a first-degree relative when aged under 50 years should be considered for thrombophilia testing.

Question 12

Is MTHFR a risk for VTE?

Answer 12

No