The circadian rhythm of blood pressure during pregnancy

Abstract

Objective: To review the literature on the circadian rhythm of blood pressure during pregnancy.

Data sources: Computerized searches on MEDLINE, CINAHL, and MIRLYN.

Study selection: Selected studies from 1 969 to 1997 were evaluated.

Data extraction: Data were extracted and information was organized under the following areas: definition of and the interconnection between circadian rhythm and blood pressure; the circadian variability of blood pressure throughout the trimesters; the patterns of the circadian rhythm of blood pressure in pregnancies defined as normal and those complicated by chronic hypertension and preeclampsia; and clinical implications.

Data synthesis: The circadian rhythm of blood pressure in pregnancy is the same as in the non-pregnant state, with a nocturnal decrease, especially during sleep. In patients with chronic hypertension, the nocturnal fall in blood pressure may be steeper. Patients with mild preeclampsia may experience a less pronounced nocturnal decrease in blood pressure. Patients with severe preeclampsia may display a reversed circadian rhythm, with no decrease and/or an increase in nocturnal blood pressure.

Conclusions: The patterns of the circadian rhythm of blood pressure during normal pregnancy and pregnancies complicated by chronic hypertension and preeclampsia warrant consideration when monitoring patients and implementing management plans.