Thromboembolism in pregnancy Flashcards
Which factors are considered risk factors for VTE in pregnancy? Presence of how many factors warrants immediate treatment?
_>_4 warrants LMWH prophylaxis:
- Age > 35
- BMI > 30
- Immobility
- Smoker
- Gross varicose veins
- Family history of unprovoked VTE
- Low risk thrombophilia
- Current pre-eclampsia
- Parity > 3
- Multiple pregnancy
- IVF pregnancy
For women at risk of VTE during pregnancy when is LMWH started and finished?
Initiated at 28 weeks and continued until 6 weeks postnatal.
If a DVT is diagnosed shortly before delivery, how long should anticoagulation be continued?
Continue anticoagulation treatment for at least 3 months, as in other patients with provoked DVTs.
Which anticoagulants should be avoided in pregnancy?
Direct Oral Anticoagulants (DOACs) and warfarin should be avoided in pregnancy.
Why is it important to prevent VTE in pregnancy?
It is the most common cause of direct maternal death in the UK (next most common is thought to be genital tract sepsis)
How common is VTE in pregnancy compared to non-pregnant state?
x6-10 more risk in pregnancy
What is the pathophysiology of hypercoagulability in pregnancy? Why does it happen?
There is:
- an increase in clotting factors VIII, IX, X and fibrinogen
- a reduction in protein S and antithrombin (AT) III
- uterus pressing on IVC causing venous stasis in legs
The net result of these changes is thought to be an evolutionary response to reduce the likelihood of haemorrhage following delivery.
What is the aetiology of VTE in pregnancy?
- Venous stasis in lower limbs - due to weight of gravid uterus on IVC in late pregnancy
- Immobilility
- Hypercoagulability of pregnancy
What conditions in pregnancy increase risk of VTE?
Specific to pregnancy:
- multiple gestation;
- pre-eclampsia;
- grand multiparity;
- C-section, especially if emergency;
- damage to the pelvic veins;
- sepsis;
- prolonged bed rest.
Which pre-existing factors increase risk of VTE in pregnancy?
Pre-existing:
- maternal age (>35 years);
- thrombophilia;
- obesity (>80 kg);
- previous thromboembolism;
- severe varicose veins;
- smoking;
- malignancy.
When do DVT/PE usually occur in pregnancy?
Third trimester
List some common heritable causes of thrombophilia.
- Deficiencies in protein S/C and AT III
- Abnormalities in procoagulant factors
- Factor V Leiden (mutated factor V gene)
- Prothrombin mutation G20210A
What is the most common acquired thrombophilia? What are its clinical features?
Antiphospholipid syndrome -
- lupus anticoagulant +/- antcardiolipin antibodies
- hx of recurrent miscarriage +/- thrombosis
- may be associated with other autoantibody disorders e.g. SLE
What are the presenting features of DVT?
- Pain calf
- Redness
- Swelling
- Unilateral symptoms
+/- PE
What investigations should be done for DVT in pregnancy?
Compression duplex USS [RCOG 2015] –> if confirmed then no further investigations needed
- Consider venography (V/Q) - injection of contrast medium and use of X-rays
What are the ECG signs of PE?
The most common ECG finding in the setting of a pulmonary embolism is sinus tachycardia.
However, the “S1Q3T3” pattern of acute cor pulmonale is classic; this is termed the McGinn-White Sign.
- A large S wave in lead I,
- a Q wave in lead III
- an inverted T wave in lead III together indicate acute right heart strain.
