Risk of first venous thromboembolism in pregnant women in hospital: population based cohort study from EnglandBMJ 2013; 347 doi: https://doi.org/10.1136/bmj.f6099 (Published 07 November 2013) Cite this as: BMJ 2013;347:f6099
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Re: Risk of first venous thromboembolism in pregnant women in hospital: population based cohort study from England
Sultan and colleagues explain the heightened risks for venous thromboembolism (VTE) in pregnant females requiring hospital admission both while in hospital and in the immediate post-discharge period . However, the concern in this context is an even further increase in the number of referrals for excluding VTE in these cases. This trend in large number of investigations in pregnancy is exemplified by a study where 149 consecutive pregnant women in a single institution were suspected to have deep vein thrombosis (DVT) and underwent compression leg ultrasonography, but the prevalence of DVT was only 8.7% .
Diagnosis of VTE in pregnancy is fraught with problems . Swollen lower limbs are common due to the pressure on the venous circulation by the gravid uterus. DVT tends to be more common in the ileofemoral vessels which are not easily imaged by ultrasound dopplers. Breathlessness can be an extremely common symptom at least in later stages of pregnancy due to various reasons including diaphragmatic splinting. Wells score and D-dimers are not validated in pregnancy. Ventilation-perfusion scanning and computerised tomography have negative implications in this special patient population due to the risks of radiation to the mother and baby .
Despite these limitations, radiological investigations to exclude venous thromboembolism in pregnancy are generally on the increase (probably going to be even more with the results from the current study). Does this come from the ‘fear of missing’ a diagnosis of fatal condition? Can a decision making process by an experienced colleague be helpful in limiting the investigations in this special population? Should diagnostic scoring systems like the LEFt rule (Left leg presentation, ≥ 2 cm calf circumference difference, and first trimester presentation - If none of the LEFt variables is present, then the negative predictive value is 100%) be applied more widely?  Can ultrasound Doppler of the lower limbs be always considered the first investigation for pulmonary embolism with the view that if there is a deep vein thrombosis, it would be treated in the same way and avoid the ‘radiation risks’? 
We need more concerted efforts in minimizing the risks of VTE in pregnancy but equally important is the efforts in minimizing the risks from unnecessary investigations in these patients.
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Competing interests: No competing interests