Yes. The very nature of the condition makes clot formation within the vessels more
likely. People suffering from this condition will almost always be aware of the fact
that they have to avoid dehydration, which increases the risk of a "sickling" crisis,
which in itself may lead to thrombosis. (See Chapter 10, "Thalassaemia and sickle
Are there any other risk factors?
The other two significant risk factors are malignancy and conditions collectively
known as "Thrombophilia syndrome".
A malignant disease (cancer) during pregnancy will tend to increase risk of thrombosis.
What is thrombophilia syndrome?
There are several chemicals and enzymes in the body, an interplay of which keep the
perfect balance in the clotting mechanism. This is a finely tuned system, which prevents
undue clotting of blood and allows and promotes this when the need arises. This may
happen when there is an injury and a clot is required to prevent excessive blood
If this balance of the clotting factors is upset, there will either be a risk of
excessive bleeding or undue clotting. In the thrombophilia syndrome, there is undue
clotting and therefore susceptibility to deep vein thrombosis (DVT).
Thrombophilia Syndrome and Pregnancy
What causes thrombophilia syndrome?
There are many factors involved in the clotting mechanism. Some of the factors' specific
function is to prevent undue clotting. Others promote clotting. When clot-preventing
factors are deficient, the risk of thrombosis is increased.
The factors that are looked for when the syndrome is suspected are:
A deficiency of any of these constitutes a diagnosis of congenital thrombophilia
Thrombophilia syndrome is also diagnosed in a case of presence of abnormal antibodies
called anticardiolipin and lupus anticoagulant. This is the so-called acquired thrombophilia.
These antibodies are also associated with recurrent miscarriage.
What is Factor V Leiden Mutation?
This is a congenital defect of one of the genes responsible for clotting factor V,
the consequence of which is increased blood coagulability and a tendency to thrombosis.
It is another variant of the congenital thrombophilia syndrome.
It is the commonest hereditary coagulation disorder with up to 1 in 20 (5%) caucasian
individuals carrying the gene mutation. The rate is just over 1% for those of black
Those with one copy of the gene mutation are called ‘heterozygous’ while those where
both gene copies have the mutation are called ‘homozygous’. There is increased risk
of thrombosis for both groups but the risk is much higher with the homozygous type.
What are the risks posed by deep vein thrombosis (DVT)?
The condition is painful. Untreated, thrombosis in a deep leg or thigh vein will
destroy the valves in that vein. This makes the vein incompetent in transporting
blood back up towards the heart. As a result, the affected person will suffer chronic
pain, leg swelling and even ulceration. This is called "post-phlebitic syndrome".
Post-phlebitic syndrome can really affect the quality of life in a negative way and
is a difficult condition to manage.
Having said all that, the more immediate concern is that of pulmonary embolism. This
is where a dislodged clot will end up lodging in a vein of a smaller calibre in the
lungs. This is a serious complication. The rough estimate is that, untreated, pulmonary
embolism will kill one in eight of its victims.
Confirming the DVT diagnosis
How can a mother-to-be suspect or recognize deep vein thrombosis (DVT)?
The affected part of the limb (usually the calf or inner thigh) will be painful and
tender. The pain may be continuous or throbbing. The area may also be swollen, red
If it is in the calf, movements of the ankle joint may cause shooting pain. If you
have any of the above symptoms, even in isolation, seek prompt medical attention.
Not all episodes of calf pain will be due to DVT, but it is best to leave it to the
experts to make the distinction.