As D-dimer level raise steadily during pregnancy, the specificity of the test decreases and it is less useful in pregnant women. A recent study suggested that the currently available sensitive D-dimer assays that are used for the exclusion in symptomatic non-pregnant women have the potential to exclude DVT in symptomatic pregnant women with the application of higher cut-points [6]. Even if this data arises from a small study, it clearly suggests that the usual cut-off set a 500 ng/ml would safely rule out DVT in pregnant women [6]. As the usual cut-off has never been prospectively validated in pregnant women with suspected DVT, we would like, as a first step, to use it in our study.