A single ultrasound scan (known as compression ultrasonography) may safely rule out a diagnosis of deep vein thrombosis (DVT) in women during pregnancy or in the first few weeks after giving birth (post-partum period), finds a study published in the British Medical Journal today.

During pregnancy the risk of DVT increases, but accurately diagnosing it is a challenge for doctors. Tests that are safe and reliable in non-pregnant patients are not always appropriate to use during pregnancy.

So a team of researchers, led by Professor Grégoire Le Gal from the University of Brest in France, set out to assess the safety of a single complete compression ultrasonography in pregnant and post-partum women with suspected DVT.

The study included 210 pregnant and post-partum women referred for suspected DVT from medical practices in France and Switzerland.

A single compression ultrasound scan was performed on each patient and anti-clotting treatment was given to those with a positive result. All women were followed up for three months.

was diagnosed in 22 (10.5%) of the 210 women. Of the 177 patients without deep vein thrombosis and who did not receive anti-clotting treatment, two patients (1.1%) experienced a confirmed DVT during follow-up.

Study limitations prevent the authors from drawing firm conclusions. Nevertheless, they suggest that a single complete compression ultrasonography "might be safe for ruling out deep vein in pregnant and post-partum women." They add that further studies are needed to confirm their findings.