HIGH NIGHT BLOOD PRESSURE IN PREGNANCY HYPERTENSIVE DISORDERS IS PREDICTIVE OF MAJOR MATERNAL AND FETAL EVENTS, ESPECIALLY DURING THE FIRST 4 HOURS OF SLEEP

Objective: We have previously demonstrated that different nocturnal blood pressure phenotypes can predict maternal and fetal events in hypertensive pregnant women. We aimed to identify whether the first 4 hours of nocturnal blood pressure values had greater significance, where slow-wave deep sleep occurs more often.Design and method: A sequencial number of hypertensive pregnant women were evaluated through ambulatory blood pressure monitoring (ABPM) with a Spacelabs 90207. An event was defined as: preeclampsia or eclampsia, foetal or neonatal death, prematurity, low weight at birth, and maternal death. Results: Our cohort was comprised of 115 pregnant women with a mean age of 33 years, with a mean of 2 CVRF, of which 31% (n=36) underwent a maternal and/or fetal adverse event. Out of these, 39% (n=45) had uncontrolled hypertension in office measurements, and 31% (n=36) had nocturnal hypertension in ABPM. Equality of means was evaluated through independant samples testing for the presence of adverse events, with number of CVRF (p=0.013), office hypertension (p=0.011), nocturnal hypertension (p=0.009), and isolated diastolic nocturnal hypertension (p=0.013) showing a significant association. Furthermore, nocturnal hypertension in the first 4 hours (p=0.016) and isolated diastolic nocturnal hypertension in the first 4 hours (p=0.022) also showed a significant association. These results were further tested through Kaplan-Meier survival curves, with nocturnal hypertension (log rank 6.2, p=0.013), isolated diastolic nocturnal hypertension (log rank 6.4, p=0.011), and nocturnal hypertension in the first 4 hours (log rank 4.3, p=0.038) all showing a significant worse survival (Figure 1). Isolated diastolic nocturnal hypertension in the first 4 hours showed a non-significant trend for worse survival (log rank 3.4, p=0.064), likely due to the lower sample size. Further confirmation was performed in a multivariate analysis through Cox model logistic regression, stratified to age, number of CVRF and office hypertension, with isolated diastolic nocturnal hypertension (HR 2.25, p=0.03) and nocturnal hypertension in the first 4 hours (HR 1.99, p=0.05) showing significantly worse prognosis. Conclusions: In our cohort of hypertensive pregnant women, nocturnal blood pressure successfully predicted maternofetal events, with the first 4 hours of sleep and diastolic values showing a significantly greater impact.