1. Venous thromboembolism (VTE) in obstetrics
Dr.Roaa H. Gadeer MD

2. Objectives Incidence Pathogenesis Predisposing factors
Clinical Presentations
Prophylaxis
Management choices
Antepartum
Postpartum

3. Incidence Deep venous thrombosis High recurrent risk: 7-13%
antepartum: per 1000 pregnancies
postpartum: per 1000 pregnancies
High recurrent risk: 7-13%
pulmonary embolus
untreated DVT: 24% have PE, 15% mortality
treated DVT: 5% have PE, 1-2% mortality

4. Number of pregnancy deaths from 1982-1992 in Canada

5. Pathogenesis of VTE in pregnancy
Stasis
Hypercoagulation
Vessel wall abnormality

6. Predisposing factors associated with pregnancy

7. Major risk factors immobility before the operation >4 days
previous hx of DVT/PE: 7-13% risk of recurrence
thrombophilias
trauma or infection
age > 35
obesity
long hospitalization
dehydration/shock
immobility before the operation >4 days
chemotherapy

8. Thrombophilias Congenital:
resistance to activated protein C (factor V leiden)
hyperhomocysteinemia (controversial)
protein S, C deficiency: 2-4% risk, 18-20% risk during postpartum
antithrombin III deficiency: 25-55% risk
Prothrombin G20210A

9. Thrombophilias Acquired:
antiphospholipid syndrome (APLS): role to cause VTE is uncertain

10. Prevalence in population
General population
Thrombosis
Factor V leiden
5-9%
20-40%
Prothrombin G20210A 3%
6-15%
Protein C def
0.3%
1-2%
Protein S
0.2%
ATIII def
0.07%
<1%
Hyperhomocystin-emia 5%
5-10%

11. Clinical Presentations
Superficial venous thrombosis
Typically associated with superficial varicosities and IV catheterization
DX and management similar to non-pregnant women

12. Clinical Presentations
2. DVT
Presentations largely depends on the degree of occlusion
Lt>Rt (80%)
Early puerperium (why?)
c/s or malpositioning in the leg holder

13. Clinical Presentations
Symptoms of DVT
calf pain, tenderness, swelling, cord, + Homan’s sign
discoloration
50% thought to have DVT have negative U/S

14. Clinical Presentations
3. PE
Leading cause of perinatal maternal loss in developed countries
Declining incidence

15. Symptoms of PE and DVT Symptoms of PE: tachypnea 80% dyspnea 81%
pleuritic pain 72%
apprehension 60%
cough 54%
tachycardia 43%
T > 37.5C 35%* in those with proven PE

16. Investigations for PE:
CXR nondiagnostic, excludes other causes of hypoxemia
ABG’s A-a gradient, maybe normal in >20%
Doppler & US
Ventilation/perfusion Lung (V/Q) scan 0.2 rads to fetus
95% correlation with venography
Spiral CT (non invasive)

17. Investigations for PE:
contrast venography, gold standard, rads to fetus for legs
pulmonary angiography, gold standard, rads to fetus, 1% maternal morbidity, 1/2000 mortality

18. Diagnosis Use US plus V/Q scan
No known human effects for fetal exposure < 5 rads
If therapy will be altered by an invasive diagnostic procedure, the benefit far overweighs the risk to mother and fetus given 15-40% mortality for untreated PE

19. PE Prevalence
Reports suggest equal distribution between antenatal and postnatal period
Higher mortality in the post partum period
Can be asymptomatic DVT until embloization develop

20. Recommendations for thromboprophylaxis
Antepartum
all pregnant women who had previous VTE should be tested for thrombophilia factors;
for single episode of prior VTE with transient risk factors: surveillance (1C)
for single episode of idiopathic VTE: surveillance or UFH or prophylactic LMWH dose (1C)
for single episode of VTE and thrombophilia (except protein S): surveillance (except decreased antithrombin) or UFH or prophylactic LMWH dose (1C)

21. Antepartum continues:
known thrombophilia: surveillance (except decreased antithrombin) or UFH or prophylactic LMWH dose (1C)
recurrent episodes of VTE: adjusted dose of UFH or adjusted dose of LMWH (1C)
> 3 moderate risk factors: surveillance or UFH or prophylactic LMWH dose (1C)

22. Recommendations for thromboprophylaxis
Postpartum
Warfarin should be offered to all postpartum women who had previous VTE (1C)

23. Low molecular weight heparin
Adjusted dose LMWH: enoxaparin 1 mg/kg sc q12h, dalteparin 200 IU/kg sc q24h
Advantages:
possibly less risk of
thrombocytopenia
osteoporosis
more predictable therapeutic effect
OD or BID administration
monitor anti-Xa levels in third trimester

24. Low molecular weight heparin
Disadvantages:
more difficult to reverse
drug cost higher but no need for hospitalization

25. IV Heparin Advantages:
inhibits thrombin by activating AT-III, prevents conversion of fibrinogen to fibrin
need baseline CBC, INR PTT
initial 5000 IU bolus, then IU/hr, INR & PTT q6hr PTT therapeutic level , then INR/PTT q24h
Advantages:
doesn’t cross placenta
not excreted in breast milk

26. IV Heparin Disadvantages:
rapidly reversible (protamine sulfate 1mg/100units)
no increase in perinatal mortality or morbidity over control
Disadvantages:
bleeding in 4-8%
osteoporosis (15,000U/d > 5 months)
thrombocytopenia (by day 4)
Cost and compliance

27. Warfarin easily crosses placenta
up to 70% fetal complications if in 1st trimester
IUGR, chondrodysplasia punctata
multiple congenital anomalies
20-30% complication rate in 2nd-3rd trimester
Long half life

28. Management during peripartum
Therapy throughout pregnancy and 8-12 weeks post partum
IV Heparin and LMWH should be held once labor is established in order to use local anesthesia
If therapeutic PTT is required in labor, patient should be switched to IV heparin
Therapeutic PTT may increase the incidence of hematomas but not PPH

29. Management during peripartum
Avoid trauma or C/S at delivery
midline episiotomy if necessary
avoid tears
Resume heparin 6 hrs postpartum
Start Warfarin when oral intake tolerated
Avoid OCP, estrogen
Consult!

30. Take home message
Thromboprophylaxis is recommended for previous VTE hx and a known thrombophilia; idiopathic VTE, recurrent VTE, and more than 3 major risk factors for VTE (II B)
Diagnosis of VTE is clinical suspicion + lab tests, never hesitate to order V/Q scan spiral CT or angiography if the result will change management
Treatment is long term: till postpartum 8-12 weeks. Considering side effects of different drugs, cost, local anesthesia, avoiding instrument delivery

31. THANK YOU