In this issue of the Netherlands Journal of Medicine, Kalk and colleagues present a retrospective analysis of 58 women with a history of pre-eclampsia out of a large cohort of women who were tested for thrombophilia. They observed a risk reduction of 45% in women who were treated with both aspirin and low-molecular-weight heparin, which did not reach statistical significance. However, as the authors discuss, this study has serious limitations. These concern issues of patient selection, the small number of observations, inadequate follow-up of the original cohort of tested women, the fact that the allocation of interventions was not randomised, and the potential of inferior quality of data recording due to the retrospective character of the study.
What this study does demonstrate is the urgent need for results from adequate, placebo-controlled trials in women with hereditary thrombophilia and pre-eclampsia, as well as other clearly defined obstetric histories. In the meantime we should not implement therapies for which we have no evidence, or in other words, in dubio, abstinae.