In women with suspected PE without symptoms and signs of DVT, a ventilation/perfusion (V/Q) lung scan or a computerised tomography pulmonary angiogram (CTPA) should be performed.
When the chest X-ray is abnormal and there is a clinical suspicion of PE, CTPA should be performed in preference to a V/Q scan.

In women with suspected PE who also have symptoms and signs of DVT, compression duplex ultrasound should be performed. If compression ultrasonography confirms the presence of DVT, no further investigation is necessary and treatment for VTE should continue.

Pregnant women with suspected PE who have symptoms and signs of DVT should have bilateral compression duplex ultrasound leg studies performed. A diagnosis of DVT may indirectly confirm a diagnosis of PE and since anticoagulant therapy is the same for both conditions, further investigation may not be necessary.

This would limit the radiation doses given to the mother and her fetus.

The algorithm suggested by the RCOG can be viewed HERE