Differences in transcranial doppler parameters between pre-eclamptic and normotensive pregnancies: a systematic review and meta-analysis.

BACKGROUND

Pre-eclampsia (PE) is a prevalent pregnancy complication that poses significant risks to neonatal and maternal health. Timely detection of PE is essential for early prevention, monitoring, and intervention to enhance patient outcomes. Transcranial Doppler (TCD) ultrasound allows non-invasive assessment of cerebral blood flow velocity and vascular resistance. This systematic review and meta-analysis aimed to synthesize available evidence to determine whether there are differences in TCD parameters between women with pre-eclampsia and those without pre-eclampsia.

METHODS

A comprehensive literature search and meta-analysis were conducted to assess the differences in cerebral artery parameters, measured by TCD, between pregnant women with pre-eclampsia and normotensive controls. These parameters, encompassing resistance index (RI), pulsatility index (PI), as well as mean blood flow velocity (MBFV), were obtained from the posterior cerebral artery (PCA), middle cerebral artery (MCA), and anterior cerebral artery (ACA).

RESULTS

Twenty-two studies involving 1,625 participants (643 PE patients and 982 controls) were included. Significant differences were found in key TCD parameters between the PE and control groups. For the MCA, MBFV increased (standardized mean difference [SMD] = 1.17; 95% confidence interval [CI]: 0.74–1.60; I² = 90.4%), whereas PI and RI decreased markedly (PI: SMD = -1.52; I² = 95.6%; RI: SMD = -1.86; I² = 94.7%). End-diastolic velocity, peak systolic velocity, and cerebral flow index showed no significant heterogeneity. For the ACA and PCA, MBFV also increased (ACA: SMD = 1.69; PCA: SMD = 1.38), while PI and RI decreased (all P < 0.001), despite substantial heterogeneity (I² > 92%).

CONCLUSIONS

The significant differences in TCD parameters between women with pre-eclampsia and normotensive controls underscore the association between pre-eclampsia and maternal cerebrovascular alterations. CLINIC TRIAL NUMBER: Not applicable.