Abstract WP544: Dynamic Cerebral Autoregulation is Impaired in the First Week Postpartum in Women With and Without Preeclampsia

Abstract

Introduction: Pregnancy, especially when complicated by preeclampsia (PEC), is associated with increased stroke risk in the early postpartum period. Impaired cerebral autoregulation may play a role in the etiology of postpartum stroke. We compared dynamic cerebral autoregulation (DCA) in 3 groups of young women: healthy non-pregnant (HNP), healthy postpartum (HP), and postpartum after severe PEC. Methods: We recruited pregnant women with and without severe PEC and compared them with historical HNP controls. Pregnant women were tested within 1 week postpartum. Subjects were monitored for 10 minutes while breathing spontaneously, using transcranial Doppler to record cerebral blood flow velocity (CBFV) in the bilateral middle cerebral arteries and finger plethysmography to record continuous mean arterial pressure (MAP). We used generalized harmonic wavelets, a combined time-frequency method, to calculate the phase shift in degrees between MAP and CBFV, with higher phase shift indicating better DCA. We compared mean phase shift between the three groups using ANOVA. Results: Data collected from 6 non-pregnant, 5 HP and 5 PEC women were analyzed. Mean phase shift was 46.3 in the HNP, 21.2 in the HP group and 30.0 in the PEC group (p<0.0001). When compared pairwise, the HP and PEC groups each had lower mean phase shift compared to non-pregnant women (p<0.001) (Figure). Conclusion: In the first week postpartum after healthy and PEC-complicated pregnancies, women had poorer DCA capacity compared with healthy young non-pregnant women. The early postpartum period may be associated with impaired autoregulation, leading to increased stroke risk, particularly in women with labile blood pressure such as occurs in PEC.