Reduced Postpartum Cognitive Function in Young Women with a History of Preeclampsia: Association with Blood Pressure Variability

Abstract

Preeclampsia is a disorder of pregnancy characterized by de novo hypertension and multi‐organ dysfunction in mid to late gestation. After pregnancy, women with a history of preeclampsia (hxPE) are at a two‐ and fourfold increased risk of incident stroke and chronic hypertension respectively. Excessive 24‐hour blood pressure variability (BPV) is exaggerated in age‐related hypertension and associated with the progression of ischemic damage to the cerebral microstructure and cognitive decline independent of average blood pressure (BP). Young women with hxPE exhibit signs of cerebral microvascular damage early after pregnancy, but the degree to which cognitive function is altered remains unknown. Furthermore, the relation between elevated BPV and cognitive function has not been assessed in women with hxPE. Therefore, the purpose of this study was to 1) establish whether cognitive function is reduced early postpartum women with hxPE compared with healthy pregnancy, and 2) determine the extent to which BPV is associated with cognitive function in women with hxPE. Women with hxPE (n=24; 32 ± 1 yrs) and healthy pregnancy controls (n=20; 33 ± 1 yrs) were assessed between 1–3 years postpartum. Participants wore an automated, portable brachial cuff for 24‐hour ambulatory blood pressure monitoring. BPV was expressed as the standard deviation (SD), coefficient of variation (CV), and average real variability (ARV) of 24‐hour ambulatory BP values. Cognitive function was assessed in domains of memory, processing speed, and executive function. Women with hxPE had reduced executive function (−0.26 ± 0.1 vs. 0.32±0.1 Z‐score; F(1,41) = 4.486, p=0.04) and slower processing speed (−0.28 ± 0.2 vs. 0.34 ± 0.2 Z‐score; F(1,41) = 4.135, p=0.050) compared with controls independent of educational attainment. Memory performance did not differ between groups. Women with hxPE had higher 24‐hour systolic BP (121 ± 2 vs. 116 ± 2 mmHg; p=0.052) and diastolic BP (78 ± 1 vs. 74 ± 1 mmHg; p=0.055) compared with controls. However, no indices of systolic or diastolic BPV differed between groups. Greater 24‐hour diastolic BPV was associated with reductions in executive function independent of average diastolic BP, age, body mass index, and education among women with hxPE (SD: r = −0.54, p=0.03; CV: r = −0.52, p=0.04) but not among controls (SD: r = 0.12, p =0.67; CV: r = 0.16, p=0.56). The relation between diastolic ARV and executive function among women with hxPE (r = −0.51, p=0.03) was lost with adjustment for education. Systolic BPV was not associated with cognitive function. Postpartum executive function was reduced and processing speed was slower among young women with hxPE compared with healthy pregnancy. Although BPV did not differ between groups, BPV was associated with reduced executive function only among women with hxPE. These preliminary findings suggest that select cognitive domains early postpartum among young women with hxPE may be more sensitive to 24 hour fluctuations in diastolic BP compared with controls. The physiologic or environm...