VTE in pregnancy Flashcards
What are the physiological changes of pregnancy that predispose to VTE
Venous stasis, trauma, hypercoagulability
Hypercoagulable
Physiological hypercoagulable state:
Increase in clotting factors, fibrinogen, PAl-1 (plasminogen activator inhibitor)
Decrease in protein S and antithrombin
Venous stasis
weight of uterus on the IVC → venous stasis (therefore more likely on the left hand side)
Which medical disorders contribute to VTE risk in pregnancy
Thrombophilia (hereditary):
- Deficiency in protein C/S/AT-III
- Abnormalities in procoagulants
- factor V leiden
- Prothrombin mutation
Acquired thrombophilia: anti-phospholipid syndrome
What are the features of antiphospholipid syndrome and how is it managed
Miscarriages (≥3) + lupus anticoagulant or anticardiolipin antibodies
- Adverse pregnancy outcomes – 3+ consecutive miscarriages before 10 weeks of gestation
- 1 or more morphologically normal foetal losses after 10w of gestation
- 1 or more preterm birth before 34-weeks of gestation
Treat with (unfractionated) heparin and aspirin → dramatically improved outcomes
It may be associated with SLE or other autoantibody disorders
When is VTE is most likely to occur in pregnancy
Most commonly in the post-partum (puerperal) period and first trimester
What are the risk factors for VTE in pregnancy
Pre-existing:
- Maternal age > 35 years
- Thrombophilia
- Obesity (> 80kg, BMI >25)
- Previous VTE
- Severe varicose veins
- Smoking
- Malignancy
- FHx of unprovoked VTE
Pregnancy-related
- Multiple pregnancy
- Pre-eclampsia
- Grand multiparity (>3)
- Caesarean section (especially if emergency)
- Damage to pelvic veins
- Sepsis
- Prolonged bed rest, travel (> 4 hours)
- IVF pregnancy
How much more likely is a pregnant woman to get VTE than a non-pregnant woman
6-10x
What are the symptoms and signs of DVT in pregnancy
Calf pain
Swelling
Abdominal pain
Unilateral, erythematous, swollen, warm, tender calf
(+cardioresp exam + obs)
What are the symptoms and signs of PE in pregnancy
SOB, dyspnoea
Chest pain (on inspiration, pleuritic - sharp, worse lying down)
Haemoptysis
Tachycardia
Mild pyrexia
(+cardioresp exam + obs)
What investigations should be done for VTE in pregnancy
Bedside: ECG (S1Q3T3)
Bloods: FBC, ABG, U&Es, LFTs, coagulation
Other
- Doppler USS legs
- CXR (If doppler -ve)
- CTPA (if CXR abnormal)
- Echo (if unstable)
- V/Q scan (Doppler and CXR normal)
- Venography
Stable
1. Doppler USS legs
- Doppler +ve: start LMWH
- Doppler -ve: CXR
2. CXR
- CXR normal: V/Q scan
- CXR abnormal: CTPA
3. V/Q scan
- V/Q scan +ve: Start LMWH
- V/Q scan -ve: CTPA
4. CTPA
- CTPA +ve: thrombolysis, start LMWH
- CTPA -ve: stop anticoagulation
Unstable
Portable echo
What is the management for DVT in pregnancy
- A-E assessment and involve senior + MDT + haematologist
- SC LMWH e.g. clexane
- Elevate the leg
- TED stockings
+ maintenance
What is the management for PE in pregnancy
- A-E assessment and involve senior + MDT + haematologist
- SC LMWH e.g. clexane
+ maintenance
What is the management for massive PE in pregnancy
- A-E assessment and involve senior + MDT + haematologist
- IV unfractionated heparin (thrombolysis)
- thrombolytic therapy
- thoracotomy
- surgical embolectomy
+ maintenance
What is the maintenance treatment for VTE
Treatment with therapeutic doses of SC LMWH should be continued for the remainder of the pregnancy and for at least 6 weeks postnatally and until at least 3 months of treatment in total
- Measure Anti-Xa if at extremes of body weight or there are complicating factors
Wear TED stockings for 2 years following DVT to prevent post-thrombotic syndrome
Why can’t warfarin be used in pregnancy
First trimester: teratogenic
third trimester: foetal intracranial haemorrhage
What are the indications for anticoagulation in labour and delivery + anaesthetic considerations
VTE occurs at term: IV unfractionated heparin → continue treatment for at least 3 months
LMWH maintenance therapy: do NOT inject any more at labour
Planned delivery: discontinue LMWH 24h prior (12h if prophylactic dose)
Anaesthetic:
- Regional i.e. epidural: must wait 24h until AFTER the last dose of LMWH
- Spinal: must wait 4h AFTER use of spinal anaesthesia or removal or epidural catheter
High haemorrhage risk: IV unfractionated heparin
How is VTE prevented in pregnant women
Mobilise early
Maintain hydration
Those with high risk (>4 risk factors) must be on prophylactic heparin from the first trimester
- If <3 risk factors - initiate LMWH from 28 weeks until 6 weeks post partum
What are the complications of VTE
DVT → PE (fatal)
Pre-eclampsia
Impaired placental circulation: IUGR, recurrent miscarriage, late foetal loss, placental abruption
Describe the use of LMWH in pregnancy
Does not cross the placenta (unlike warfarin and DOACs)
As safe and effective as unfractionated heparin with lower and fewer haemorrhagic complications
Following delivery, women can choose to convert to warfarin
LMWH and warfarin are both safe in breastfeeding
Given to anyone with signs or symptoms suggestive of VTE until excluded
If suspected PE in the presence of confirmed DVT- treat with therapeutic dose LMWH IMMEDIATELY.
The therapeutic dose should be calculated based on the woman’s booking or early pregnancy weight
What constitutes high risk for VTE in pregnancy antenatally and what should be done for these patients
Any previous VTE (except a single event related to major surgery)
→ VTE prophylaxis with LMWH
What constitutes high risk for VTE in pregnancy postnatally and what should be done for these patients
Any previous VTE
Anyone requiring antenatal LMWH
High-risk thrombophilia
Low-risk thrombophilia + FHx
→ at least 6 weeks postnatal prophylactic LMWH
What are the intermediate risk factors for VTE in pregnancy and what should be done for these patients
Hospital admission
Single previous VTE related to major surgery
High-risk thrombophilia + no VTE
Medical comorbidities e.g. cancer, HF, SLE, IBD, nephrotic, T1DM + nephropathy, SCD, IVDU
Any surgical procedures
OHSS in the first trimester
→ consider prophylaxis with LMWH
sWhat are the intermediate risk factors for VTE postnatally and what should be done for these patients
Caesarean section in labour
BMI >40
Readmission or prolonged admission >3 days
Any surgical procedure in the puerperium except immediate perineal repair
Medical comorbidities e.g. cancer, HF, SLE, IBD, nephrotic, T1DM + nephropathy, SCD, IVDU
→ at least 10 days prophylactic postnatal LMWH
What are the minor risk factors for VTE in pregnancy and what should be done for these patients
Obesity, BMI >30
Age > 35
Parity > 3
Multiple pregnancy
Smoker
Gross varicose veins
Current pre-eclampsia
Immobility
FHx unprovoked VTE
Low-risk thrombophilia
IVF/ART
Preterm delivery, prolonged labour, PPH
Stillbirth
Instrumental delivery
→ 4 or more → prophylaxis from first trimester
→ 3 or more → prophylaxis from 28 weeks
→ fewer than 3 → mobilise and avoid dehydration
Postpartum → 2 or more → 10 days postnatal prophylaxis
