REVERSED CIRCADIAN BLOOD-PRESSURE RHYTHM PRESERVES FETAL GROWTH IN PREECLAMPTIC PREGNANCY

Objective: To determine the clinical trait of hypertension in pregnant women with a reversed circadian blood pressure (BP) rhythm. Study des ign: 24-h BP monitoring was performed in 56 hypertensive pregnant wome n, of whom 12 had a reversed systolic BP (SEP) rhythm (day/night mean BP ratio <1.0). Clinical data, ultrasound fetometry and umbilical arte ry velocimetry were compared to that in women with a normal rhythm. St atistical analyses were performed with simple linear regression, Mann- Whitney U test, analysis of variance, contingency table analysis and F isher's test. A two-tailed P value of <0.05 was considered significant . Results: In the reversed SEP group, the nighttime BP, fetal weight, albuminuria and S-urate were higher, and the BP variations smaller. Th e birthweight correlated negatively to the SEP day/night ratio. Higher SEP day/night ratios and larger BP variations were associated with an increased vascular resistance in the umbilical artery and an impaired growth. Conclusion: A reversed SEP rhythm was associated with a more severe degree of preeclampsia, but also with a smaller BP variation, m aintenance of fetal growth, and higher birthweight. A sustained high n ighttime BP preserved fetal growth. These novel observations challenge the opinion that a reversed circadian BP rhythm is merely an ominous sign. (C) 1997 Elsevier Science Ireland Ltd.