Ambulatory blood pressure normalcy in pregnancy.

Ambulatory blood pressure monitoring (ABPM) is increasing in popularity for evaluation of hypertensive status. ABPM is also employed for measurement of BP during pregnancy to prevent both motherʹs and foetusʹs health risk. We measured Clinic (the average of three measurements sphygnomanometry), ABPM (automatic readings at 15 minutes intervals, Spacelabs 90207) and Home values (averages of morning and evening measurements, semiautomatic device, Philips HP 5331, Japan) during gestational weeks 20 to 22 (1st trimester), 30 to 32(2nd tromester), 35 to 37(3rd trimester). At the same time we also performed ultrasonography to evaluate the foetusʹs well-being. We here present only blood pressure (BP) data obtained from 24 women (mean age 32 +/−4 range 25-42) who ended the protocol. All BP showed a normal distribution and ABPM (2,6 average readings per hour) showed similar values in the morning and the afternoon hours and a marked nocturnal BP fall. Home BP (average of two measurements) was markedly lower than Clinic BP and similar to ABPM values in the three trimester. All BP values were lower in pregnant women during the 1st trimester than in non pregnant age matched women selected from a general population and showed a gradual increase during the 2nd and the 3rd trimester, when they were similar to ones of the general population. There was a correlation between Clinic, Home and ABPM values (r above 0,7) for systolic BP, while for diastolic BP the correlation was significant only between Home and ABPM. Because of there were no correlation between Clinic, Home and ABPM diastolic BP, we use as upper limit of normality the value of 140 mmHg Clinic systolic BP. With this cut off the corresponding values for both ABPM systolic BP and Home systolic BP are 121 mmHg and 123 mmHg for the 1st trimester, 123 mmHg and 125 mmHg for the 2nd trimester, 123 mmHg and 125 mmHg for the 3rd trimester. Home BP might represent a satisfactory (and cheaper) indicator of 24h mean values. We suggest the use of 140 mmHg Clinic SBP to obtain the corresponding values of both 24h mean and Home BP.