Severe preeclampsia and cerebral blood volume response to postural change

To compare the cerebral blood volume response, measured by near-infrared spectroscopy, to a change in maternal posture in pregnant women with and without the hypertensive disorders of pregnancy.

Normotensive (n = 13), chronic hypertensive (n = 7), pregnancy-induced hypertensive (n = 9), and preeclamptic (n = 15) women were studied cross-sectionally. The change in cerebral blood volume in response to a change in maternal posture from the left lateral to sitting position was quantified.

In the normotensive, chronic hypertensive, and pregnancy-induced hypertensive groups there was a fall in median (interquartile range) cerebral blood volume of 0.18 (-0.21, -0.15), 0.11 (-0.26, -0.09), and 0.089 (-0.10, -0.049) mL/100 g, respectively. Conversely, in the preeclamptic group there was a rise in median cerebral blood volume of 0.13 (-0.20, 0.15) mL/100 g. Of these, six of the nine women with a median rise in cerebral blood volume of 0.15 mL/100 g (0.13, 0.16) required intravenous antihypertensive therapy, volume expansion, and delivery by cesarean within 48 hours. Conversely, none of the preeclamptic women (n = 6) with a median fall in cerebral blood volume of 0.22 mL/100 g (-0.30, -0.18) required these emergency measures.

The cerebral blood volume response, measured noninvasively by near-infrared spectroscopy, provides additional evidence of altered cerebral hemodynamics in women with preeclampsia.