By: Hanaa Adnan Rasheed6th stage Group B1

Supervised by: Prof.Dr. Ayla K. Ghalib

Points to Discuss:

1) Physiology of hemostasis.

2) Coagulation during pregnancy.

3) Thromboembolism in pregnancy:

• Superficial thrombophlebitis.

• Deep vein thrombosis.

• Pulmonary embolism.

• Thrombophilias.

4) Thromboprophylaxis.

Physiology of Hemostasis:

The term hemostasis means prevention of blood loss.

Whenever a vessel is severed or ruptured, hemostasis is achieved by several mechanisms:

(1) vascular constriction,

(2) formation of a platelet plug,

(3) formation of a blood clot as a result of blood coagulation, and

(4) eventual growth of fibrous tissue into the blood clot to close the hole in the vessel permanently. (1)

The extrinsic pathway

begins with a traumatized

vascular wall.

The intrinsic pathway

begins with trauma to the

blood itself or exposure of

the blood to collagen from

a traumatized blood vessel

wall. (1)

Coagulation During Pregnancy:

Plasma Fibrinogen concentration by ~

50%.

Factors: V, VII, VIII, IX, X and XII.

Platelet reactivity in 2nd and 3rd TMs till

12wk post partum.

Fibrinolytic activity.

Protein S (an inhibitor of coagulation). (2)

Pregnancy is a hypercoagulable state that

return to normal 4 weeks after delivery. (3)

WHY???

This hypercoagulability is particularly relevant at delivery, with placental separation…

At term, around 500ml blood flows through the placental bed every minute…

Without effective and rapid hemostasis, a woman could rapidly die from blood loss…

Myometrial contraction FIRST compress BV supplying placental bed…

Then FIBRIN deposition on pl. bed.(10% of blood fibrinogen is used for this process!). (3)

Thromboembolism in Pregnancy:

1. Superficial Thrombophlebitis

2. Deep Vein Thrombosis.

3. Pulmonary Embolism.

4. Thrombophilias.

Venous Thromboembolism (VTE)

Venous thromboembolism (VTE) is the leading

direct cause of maternal death throughout

pregnancy.

The incidence of thromboembolic complications,

pulmonary TE and DVT presented during

pregnancy is around 1/1000, with a further

2/1000 women presented in puerperium.

VTE is up to 10 times more common in

pregnancy than in comparable non-pregnant

subject. (2)

Hyper-

coagulability

Vascular Damage

Venous Stasis

Pathogenesis of VTE in Pregnancy

Risk Factors for VTE in Pregnancy (4)

Risk FactorsTimeframe

Previous venous thromboembolism

Thrombophilia

Medical comorbidities (e.g. heart or lung disease, SLE,

cancer, inflammatory conditions , nephrotic syndrome ,

sickle cell disease,

Age > 35 years

Obesity (BMI > 30 kg/m2)

Parity ≥ 3

Smoking

Gross varicose veins

Paraplegia

Pre-existing

Multiple pregnancy, assisted reproductive therapy

Pre-eclampsia

Caesarean section

Prolonged labour, mid-cavity rotational operative delivery

PPH (> 1 litre) requiring transfusion

Obstetric

Surgical procedure in pregnancy or puerperium

Hyperemesis, dehydration

Ovarian hyperstimulation syndrome

Potentially

Reversible

1* Superficial Thrombophlebitis

Clinical Features:

Swelling and tenderness of the involved extremity.

On physical examination, there is erythema, tenderness, warmth, and a palpable cord over the course of the involved superficial veins.

Treatment:

Bed rest, pain medications, and local application of heat are often sufficient treatment.

There is no need for anticoagulants, but anti-inflammatory agents may be considered. (5)

2* Deep Vein Thrombosis:

Clinical Features:

50% of cases are

asymptomatic.

DVT is much more common in

the left than the right leg.

Pain in the calf in association

with dorsiflexion of the foot

(positive Homans’ sign) .

Dull ache, tingling, tightness,

especially when walking. (5)

Investigations (6) :

3* Pulmonary Embolism:

Clinical Features:

Symptoms: - Pleuritic chest pain,

- Shortness of breath,

- Air hunger,

- Palpitations,

- Hemoptysis

Signs: º Tachypnea,

º Tachycardia,

º Pleural friction rub,

º Pulmonary rales,

º Signs of right ventricular failure. (5)

Investigations (6)

Other

investigations:

ECG

Arterial blood

gases

*CUS=

Compression

Ultrasound.

*CTPA=CT

pulmonary

Angiography.

*V/Q=

Ventilation

Perfusion Scan

Perfusion Ventilation

Treatment of VTE in Pregnancy:

Acute Phase Treatment:

• Thrombolytic Therapy:

• Streptokinase and TPA.

• Cannot be recommended in pregnancy except in life saving procedures:

• Skocked patient with massive PE.

• Iliofemoral venous thrombosis.

• Anticoagulants:

• Unfractionated Heparin:

• 40.000 IU/day

• IV infusion

• For (3-7) days

• Monitor by APTT (1.5-2.5)x normal.

• Fractionated or LMWH:

• Surgery.

Chronic Phase Treatment:

• Warfarin:

• Cross placenta

• If given in pregnancy it must be stopped at 36 wk.

• Monitor by PT and INR (target 2.0 – 3.0).

• Duration of action: 3 days

• S.E: bleeding tendency & teratogenecity.

Teratogenic Effects of Warfarin:

• Embryopathy.

• CNS abnormalities.

• ↑abortion and premature labour.

• Chondroplasia punctata.

• Nasal hypoplasia.

4* Thrombophilias

Congenital

• Anti-thrombin III deficiency

• Protein C deficiency

• Protein S deficiency

• Factor V Leiden

• Prothrombin gene variant

Acquired

• Antiphospholipid syndrome (2)

Antiphospholipid syndrome (APS)

Antiphospholipid antibodies are circulating

antibodies to negatively charged phospholipids.

They include lupus anticoagulant and

anticardiolipin antibodies.

Antiphospholipid antibody syndrome is defined

as the presence of at least one antibody in

association with arterial or venous thrombosis with

or without one or more obstetric complication

(unexplained fetal demise after 10 weeks’

gestation or severe preeclampsia or fetal growth

restriction before 34 weeks’ gestation).

Treatment: LMWH and Aspirin. If Hx of

thrombosis, require full anticoagulation. (5)

References:

1. Arthur C. Guyton. Guyton Textbook of Medical

Physiology. Elsevier Saunders. 11th edition.

2006. pages (419-468).

2. Edmonds D. Keith. Dewhurst’s Textbook of

Obstetrics and Gynecology. Blackwell

publishing. 7th edition. 2007. pages (270-281).

3. Philip N. Baker. Obstetrics by Ten Teachers.

Hodder Arnold. 18th edition. 2006. Pages (286-

299).

4. Reducing the Risk of Thrombosis and

Embolism During Pregnancy and Puerperium.

RCOG green top guideline. American College

of Obstetricians and gynecologists. No.37a.

November 2009. pages (1-35).

5. Neville F. Hacker, Josephe C. Gambone and

Calvin J. Hobel. Hacker and Moore’s

Essentials of Obstetrics and Gynecology.

Elseviers Saunders. 5th edition. 2010. pages

(191-218).

6. Cunningham F. Gary, Kenneth J. Levendo,

Steven L. Bloom et al. Williams Obstetrics.

Mc Graw Hill. 24th edition. 2014. Pages

(1028-1047).