Predictable blood pressure variability in clinically healthy human pregnancy

Changes in 24-h synchronized (circadian) characteristics of blood pressure (BP) and heart rate (HP) are quantified in two consecutive pregnancies of a clinically healthy woman. BP and HR were automatically monitored, with few interruptions, at 1-h intervals, and for a total of 76 days of monitoring in each pregnancy. Circadian parameters of BP and HR were computed for each single day of measurements by the least-squares fit of a 24-h cosine curve. Regression analysis of parameters thus obtained revealed patterns of variation of circadian rhythm-adjusted means and amplitudes with gestational age. This longitudinal study confirms and extends to ambulatory everyday-life conditions the predictable pregnancy-associated variability in BP and HR, and also allows the establishment of prediction and confidence limits for cardiovascular parameters in a healthy pregnancy