The transcranial Doppler of maternal cerebral arteries and the prediction of pre-eclampsia

Background: Pre-eclampsia is a major cause of maternal and perinatal death. Parameters derived from the Doppler waveform in different vascular beds have been studied as possible predictors of pre-eclampsia. Objectives: To assess whether second –trimester changes in transcranial Doppler parameters of normotensive pregnant woman are associated with the subsequent development of pre-eclampsia. Search Strategy: The strategy for identification studies was based on the search performed in electronic databases. In addition, reference lists of retrieved articles were checked. Selection Criteria: We selected all case-control and cohort studies providing measures of cerebral arteries parameters by transcranial Doppler among normotensive women in the secondtrimester of pregnancy. Data collection and analysis: We assessed studies for methodological quality, according to the Critical Appraisal Skills Programme. One reviewer assessed the studies for inclusion and extracted data. The outcome we sought was the occurrence of pre-eclampsia / eclampsia. Main Results: Three studies involving 485 women were included. Considering the heterogeneity of data a meta-analysis of these was considered not feasible. One cohort study observed that the maternal middle cerebral artery blood flow velocity assessed by transcranial Doppler did not show any ability to predict the occurrence of pre-eclampsia. One case-control study observed that the middle cerebral arteries pulsatility and resistance indices were lower in the second trimester in the women who later would develop pre-eclampsia. Another case-control study did not corroborate this predictive capacity. Reviewers' conclusions: Further research is needed to define the ability of transcranial Doppler in the prediction of pre-eclampsia. Until further evidence is available, the transcranial Doppler may not be performed to predict or promote the earlier detection of pre-eclampsia.