How is suspected pulmonary embolism be investigated?
When a pregnant woman or a newly delivered woman has clinical symptoms suggestive
of pulmonary embolism, it is dealt with as an emergency.
If there is strong suspicion, treatment will start even before confirmatory tests
This is because pulmonary embolism is a truly serious complication, which could easily
and quickly lead to a fatal outcome.
Of course, if tests establish a different diagnosis, treatment can be stopped with
peace of mind.
Investigations carried out include blood analysis to check gases (including oxygen
and carbon dioxide), chest X-ray, plain CT and ECG. All these are non-specific and
the diagnosis may still remain elusive. If this is the case, then a more specialized
test called a V/Q scan (also called a ventilation perfusion scan) is then performed.
This is very sensitive and, even though it is not foolproof, if a pulmonary embolism
is ruled out by a V/Q scan, there is almost certainly no danger to the patient. Another
quite sensitive alternative is a CT pulmonary angiogram (CTPA)
So should everybody suspected to have a pulmonary embolism have this special (V/Q)
scan or the CTPA performed?
Not necessarily. The attending clinicians will decide if this is the appropriate
course of action. There are a lot more mundane conditions which could mimic this
serious condition, including such things as muscle or ligament sprain, pressure pain
from the fetal limbs in late pregnancy under the ribs and self-limiting viral respiratory
But a chest X-ray involves radiation. Isn't this dangerous in pregnancy?
Yes, a chest X-ray involves radiation. So does a V/Q scan. However, precautions are
taken to shield the womb and its contents. Moreover, the amount of radiation involved
is considered safe. A V/Q scan involves a dose of radiation that is one-tenth of
the maximum dose considered safe in pregnancy. A chest X-ray involves an even lower
Treatment for pulmonary embolism in pregnancy
What is the treatment for pulmonary embolism?
Again, it is the anticoagulant heparin. In pulmonary embolism, this will be given
in the form of continuous infusion at a much higher dose than that used in uncomplicated
deep vein thrombosis. Special tests will be carried out regularly to ensure that
the right effective dose is being given. This may continue for a few days before
switching to heparin injections. Treatment will continue for the remainder of the
pregnancy and for six to eight weeks after delivery, sometimes longer.
Is this treatment always successful?
In the majority of cases, yes. In some very serious cases, this may be insufficient
and very specialized surgical intervention may be necessary as a life-saving measure.
This is rare.
Is heparin safe to use in pregnancy?
Heparin does not cross the placenta and therefore, as far as the baby is concerned,
it is perfectly safe. Regular tests will be carried out to ensure that an optimal
dose is being given to the mother. Too much heparin can cause bleeding tendencies
and, if tests show evidence of this, the dose will be adjusted downwards. Another
problem associated with prolonged heparin use has been the risk of osteoporosis.
In rare instances, this has been known to lead to bone fractures. However, the benefits
of treatment far outweigh the potential risk.
Do the low-molecular weight heparins also pose the risk of osteoporosis?
Yes, but to a much lower degree. The preparations commonly used in the UK are known
under the brand names Fragmin® (Dalteparin), Clexane® (Enoxaparin) and Innohep® (Tinzaparin).