Venous thromboembolism (VTE), which includes deep vein thrombosis and pulmonary embolism, can occur during pregnancy. The risk of VTE is highest during the antepartum period and with cesarean delivery. Risk factors include prior VTE, thrombophilia, older age, obesity, multiparity, bed rest, and certain medical conditions. Treatment involves anticoagulants like heparin and warfarin, with heparin preferred in early pregnancy due to risks of warfarin exposure to the fetus. Patients are classified as very high, high, moderate, or low risk, with treatment strategies varying based on risk level.

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VENOUS THROMBOEMBOLISM DURING PREGNANCY
1A-MOWAFY 2013
VTE = Venous thromboembolism
Includes; Deep venous thrombosis DVT, Pulmonary embolism PE
INCIDENCE :
 2-3 in 1000 pregnancies
 DVT 80% PE 20%
 2/3 of DVT are antepartum
 Caesarean section increases the risk 3-5 fold than vaginal delivery
PATHOGENESIS
Virchow’s triade =
1. Circulatory stasis
2. Vascular damage
3. Increased blood co-agulation
AETIOLOGY
Risk factors:
1. Pregnancy itself is a risk factor
2. Previous VTE in patient on hormonal contraception
3. Previous VTE during pregnancy ( risk is 12 % )
4. Rheumatic heart disease and patients with heart prosthesis
5. Thrombophilias (congenital and acquired?!)
6. Age ˃ 35 years old
7. Obesity ; BMI ˃ 30
8. Multiparity ; parity ˃ 4
9. Recurrent miscarriage
10. Bed rest and physical immobility
11. Hyperemesis gravidarum
12. Shock and dehydration
13. Infections
Venous thromboembolism
during pregnancy
Venous thromboembolism during pregnancy

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VENOUS THROMBOEMBOLISM DURING PREGNANCY
2A-MOWAFY 2013
14. Pregnancy-induced hypertension
15. Excessive blood loss
16. Prolonged labour
17. Instrumental delivery
18. Cesarean section
19. Pelvic surgery in peri-partum period
20. Sickle cell anemia
21. Gross varicose veins
22. Fetal demise with remaining viable fetus
23. Intra-uterine gross restriction IUGR
Q: What is thrombophilia?
It is abnormalities in the blood co-agulation that is increases the risk of thrombosis;
(congenital, Acquired?)

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VENOUS THROMBOEMBOLISM DURING PREGNANCY
3A-MOWAFY 2013
RISKY GROUPS AND THEIR MANAGEMENT:
Very high risk
Criteria  Previous VTE with thrombophilia
 Long term warfarin therapy
Antepartum  High prophylactic dose or therapeutic dose of LMWH
Postpartum  LMWH for 5 days + Warfarin
High risk
Criteria  Previous recurrent VTE
 VTE once with thrombophilia
 VTE once with positive family history
 Diagnosed important thrombophilia
 Valvular mechanical prosthesis
Antepartum  prophylactic dose LMWH
Postpartum  LMWH for 5 days + Warfarin for 6 weeks
Moderate risk
Criteria  Single provoked VTE without thrombophilia
 Thrombophilia + Anti-thrombin III deficiency
 Mitral stenosis
Antepartum  Antenatal aspirin
Postpartum  LMWH for 5 days + Warfarin for 6 weeks
Low risk
Criteria Two or more of the following :
 Obesity
 Age ˃ 35
 Parity ˃ 4
 Gross varicose veins
 Recurrent hypertensive disorders
Antepartum  Antenatal aspirin
Postpartum  Warfarin for 6 weeks

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VENOUS THROMBOEMBOLISM DURING PREGNANCY
4A-MOWAFY 2013
ANTI-COAGULANT DRUGS:
Heparin
Types I. Unfractionated heparin → UFH “Cal-heparin”
II. Low molecular weight heparin → LMWH “Clexan”
Onset Within 10 minutes
Half-life 6 hours
Doses
I. Unfractionated heparin
 Normal body weight → 5000 IU/day
 Body weight ˂ 50 kg → 2500 IU/day
 Body weight ˃ 90 kg → 5000 IU/12 h
 High prophylactic dose→ 100 IU/kg/12h
II. Low molecular weight heparin
 Normal body weight → 40 mg/day
 Body weight ˂ 50 kg → 20 mg /day
 Body weight ˃ 90 kg → 40 mg / 12h
 High prophylactic dose→ I mg/kg/12h
Monitoring 1. Activated partial thromboplastin aPPT twice weekly
2. Plattlets concentration monthly
3. Bone mineral density every 3 months
Advantages
1. No effect on the fetus ( does not cross placental blood barrier )
2. Not secreted on milk ( no effect on lactation )
N.B : advantages of LMWH over UFH
o Fewer side effect
o Prolonged half-life
o Greater inhibitory effect on factor X
o Prophylactic dose once daily
o No need for continuous laboratory monitoring
Drawbacks  Increase bleeding tendency
 Osteoporosis ( improved by adding calcium , hence name “ Cal-heparin “
 Fat necrosis at site of injection
 Alopecia
Anti-dot Protamine sulphate 1mg/100IU

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VENOUS THROMBOEMBOLISM DURING PREGNANCY
5A-MOWAFY 2013
Oral anti-coagulant drugs
Types I. Coumarine → Warfarin sodium “Marevan”
II. Indandione → phenoidione “Dindevan”
Onset Full effect after 5 days
Half-life  Warfarin → 44 hours
 Phenoidione → 5 hours
Doses 2 to 5 mg/day
Monitoring 1. INR = “ international randomized ratio “→ should be 2 to 3
2. PT = “ prothrombine time “→ 30–50 % of normal control
Advantages Oral route , potent and long acting
Drawbacks  Maternal :
1. Skin: allergy, fever, rash, urticarial and dermatitis
2. Blood: agranulocytosis
3. Liver: liver disturbances; jaundice
4. Renal: renal disturbances; hematuria
5. Over dose → bleeding tendency
 Fetal :
1. Warfarin embryopathy; nasal hypoplasia, depression of nasal bone, mental
retardation, optic atrophy, skeletal defect ‘ bone splitting’
2. Can cross placental-blood barrier; bleeding tendency and increases the risks
of intracranial hemorrhage and accidental hemorrhage
 Drug interactions :
1. drugs increases the effect : salicylates, quinine, steroids
2. drugs decreases the effect : hepatic enzyme inducers
Anti-dot  Vitamin K IM. , SC.
 For rapid effect :
1. Fresh blood , fresh frozen plasma
2. Vitamin K to the mother and baby
PROTOCOLS FOR ANTI-COAGULATION DURING PREGNANCY
Frist trimester → only heparin for fear of warfarin embryopathy
Second trimester → warfarin starting from 13 weeks
Continue till:
 33 weeks if risk of preterm laobour exist
 36 weeks if no risk of preterm labour
However, oral anti-coagulants are not absolutely safe as delayed warfarin
embryopathy is recorded
Late in pregnancy: at 33 – 36 weeks → shift to heparin again
Postpartum: Vitamin K to the mother and baby and readjust the dose