Venous Thromboembolism In Pregnancy
By
Prof.Osman Donia
INTRODUCTION AND
INCIDENCE
• Pregnancy is a known hyper-coagulable
state, with a five-fold risk of venous
thromboembolism over the non-pregnant
condition
• 0.5 and 3 of every 1000 pregnancies are
complicated by symptomatic deep venous
thrombosis (DVT).
• 25% may develop pulmonary embolism
(PE), of which up to 15% are fatal.
AETIOLOGY
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Increase in the levels of coagulation
factors VII, VIII, IX, and X.
Increased fibrinogen levels.
Increased platelet activation.
Decreased protein-S and Antithrombin III
concentrations.
Venous stasis in the lower limbs due to
pressure by the gravid uterus
THROMBOPHILIA
• Acquired thrombophilia
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This is mostly associated with the
antiphospholipid syndrome (APS). APS is the
combination of lupus anticoagulant (LAC) with or
without, anticardiolipin antibodies (ACA), with a
history of recurrent miscarriage and or
thrombosis.
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Inherited thrombophilias
Protein-C, protein-S, and Antithrombin III
deficiency.
Risk factors for DVT / PE during
pregnancy
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Maternal age > 35 years.
Pre-pregnancy weight > 80 kg.
Pre-existing Thrombophilia.
Previous DVT.
Severe varicose veins (V.Vs).
Prolonged bed rest.
Multi foetal pregnancies.
Severe pre-eclampsia.
Caesarean section delivery.
Sepsis, especially pelvic.
DEEP VEIN THROMBOSIS (DVT)
• CLINICAL DIAGNOSIS
• DVT usually presents clinically with pain
in the calf muscles associated with
varying degrees of redness, hotness, or
swelling, especially unilateral oedema.
DEEP VEIN THROMBOSIS (DVT)
• INVESTIGATIONS
• Colour Doppler Ultrasound: It allows assessment of
the deep veins between the knee and the iliac veins and
also allows for the dynamic assessment of femoral and
iliac veins. It is currently the preferred first-line method
for investigating a suspected case of DVT during
pregnancy being an accurate, non-invasive procedure.
• Venography: This allows excellent visualization of veins
both below and above the knee. However it is an
invasive procedure, requiring the injection of a contrast
medium and the use of X-ray. This method is not
preferable during pregnancy.
DEEP VEIN THROMBOSIS (DVT)
• MANAGEMENT
• Anticoagulant therapy
• 1. Heparin and LMW heparin derivatives: The
preferred initial line of treatment, as they do not cross the
placenta, are not teratogenic, and their effect can be
stopped within hours by withholding further doses.
Heparin prolongs the activated partial thromboplastin
time (APTT), while calcium heparins affect factor X
activity.
• These drugs are regarded relatively safe; however
prolonged therapy for more than 6 months may be
associated with idiosyncratic reaction, thrombocytopenia
and higher risk of osteoporosis.
DEEP VEIN THROMBOSIS (DVT)
2. Oral anticoagulants: Warfarin prolongs
the prothrombin time (PT). The drug
crosses the placenta and can cause limb
and facial defects in the first trimester, and
fetal intracerebral haemorrhage in the third
trimesters. Recently some centres use it in
the 2nd trimester.
DEEP VEIN THROMBOSIS (DVT)
• Anticoagulant prophylaxis
• Women with a history of DVT occurring during or
following a previous pregnancy are given prophylactic
LMW heparin derivatives during subsequent pregnancies
at least in the last trimester that extends at least to the
end of the puerperium.
• Women with a history of DVT occurring in the nonpregnant state should be screened for thrombophilias,
and offered anticoagulant prophylaxis at least starting
from the second trimester.
• Some women will require full anticoagulation throughout
pregnancy as those with artificial heart valves and cases
of APS with recurrent DVTs, or cases with a definite
history of previous pulmonary embolism.
PULMONARY EMBOLISM (PE)
• PE is one of the fatal consequences of undiagnosed or
improperly managed cases of DVT.
• Clinical presentation
• The most common presentation is mild breathlessness
with inspiratory chest pain.
• Associated tachycardia, hypoxia, pleural rubs and
sometimes ECG changes will settle the clinical
diagnosis.
• A history of recent DVT event or the presence of clinical
evidence of pelvic or lower limb DVT is an important clue
for diagnosis and immediate management.
PULMONARY EMBOLISM (PE)
• Management
• Once suspected, early intervention by full I.V.
anticoagulant therapy may be life saving. Full
I.V. heparinization is immediately started, with
supportive oxygen therapy.
• Definitive diagnosis is then required via
ventilation / perfusion scan or pulmonary
angiography. A positive diagnosis of PE will
have a major impact regarding long-term
anticoagulation.