AMBULATORY MONITORING OF BLOOD-PRESSURE IN NORMAL-PREGNANCY

The definition of hypertensive disorders in pregnancy is plagued by ma ny difficulties, in part related to the limits of intermittent clinic readings of blood pressure. In order to better define the evolution of arterial blood pressure in normal subjects during normal pregnancy, c asual and ambulatory (Spacelabs 90207, n = 22 or Diasys 200, n = 26) m easurements of blood pressure were performed at gestational months 3, 6, and 9, in 48 normal women aged 18 to 39, both nulliparas (n = 19) a nd multiparas (n = 29). Ambulatory blood pressure levels were lowest i n the first gestational trimester (24-hour mean: 104 +/- 8/63 +/- 6 mm Hg) and rose by a small increment during the last trimester (109 +/- 8/67 +/- 7 mm Hg at 8 months). Mean daytime ambulatory pressure was al most superimposable to clinic measurements at the three time points. A day-night variation in blood pressure level was detectable in all sub jects at each recording. It is concluded that during normal pregnancy, ambulatory blood pressure levels were highest in the day and lowest a t night at all gestational ages and increased only minimally before th e ninth month. Reference values, as defined by the percentile distribu tion of daytime and nighttime systolic and diastolic blood pressure, m ay help define more precisely an alteration in the level and/or the ci rcadian variation of arterial blood pressure during abnormal pregnanci es.