Diagnosis Of Gestational Hypertension Research Articles

Circadian Rhythm of Blood Pressure Challenges Office Values as the “Gold Standard” in the Diagnosis of Gestational Hypertension

Despite poor sensitivity and specificity, office blood pressure (BP) determinations are still the “gold standard” for diagnosing gestational hypertension. This prospective blind study evaluates the prognostic value of office values as compared with ambulatory monitoring in pregnancy. We analyzed 2175 BP series systematically sampled from 355 non-preeclamptic pregnant women for 48 h every 4 wks from the first hospital visit until delivery. Women were divided for comparative purposes into three groups: “detected” gestational hypertension, defined on the basis of casual clinical BP>140/90 mm Hg after 20 wks of gestation and hyperbaric index (area of BP excess above the upper limit of a time-specified tolerance interval adjusted for the circadian pattern of the reference population) consistently above the threshold for diagnosing hypertension in pregnancy; “undetected” gestational hypertension, women with office BP<140/90 mm Hg but hyperbaric index consistently above the threshold for diagnosis; and normotension, women with both office values and hyperbaric index below the respective thresholds for diagnosis. Small and insignificant differences in the 24 h mean BP between “detected” and “undetected” gestational hypertension is observed in all trimesters, in contrast with highly significant differences between these two groups and normotensive pregnancies. Normotensive women are characterized by highly significant lesser incidence by 60% in preterm delivery, 70% in intrauterine growth retardation, and 50% in delivery by cesarean section (P<0.001) compared with women with “detected” and “undetected” gestational hypertension (P>0.715). In pregnancy, the hyperbaric index is markedly superior to office BP measurements for diagnosis of what should be truly considered gestational hypertension, and for prediction of the outcome of pregnancy.

Diurnal, nocturnal or 24-hour mean blood pressure values for the diagnosis of gestational hypertension. which should be used?

Diurnal, nocturnal or 24-hour mean blood pressure values for the diagnosis of gestational hypertension. which should be used?

Time-qualified reference values for ambulatory blood pressure monitoring in pregnancy.

To recognize the highly statistically significant circadian variability of blood pressure in pregnancy is to admit that the diagnosis of gestational hypertension or preeclampsia should be based not just on whether a casual blood pressure value is too high or too low, but rather on more pertinent questions: How long is blood pressure elevated above a given time-varying threshold? What is the excess blood pressure? When does most of the excess occur? Answers to these questions may be obtained by establishing (1) an adequate reference threshold for blood pressure and (2) a proper measurement of blood pressure elevation. Accordingly, we derived time-specified reference standards for blood pressure as a function of gestational age. We analyzed 1408 blood pressure series systematically sampled by ambulatory monitoring for 48 consecutive hours every 4 weeks from the first obstetric visit (usually within the first trimester of pregnancy) until delivery in 235 women with uncomplicated pregnancies. Data from each blood pressure series were synchronized according to the rest-activity cycle of each individual to avoid differences among women in actual times of daily activity. Data were then used to compute 90% circadian tolerance intervals for each trimester of pregnancy, in keeping with the trends in blood pressure along gestation previously documented. The method, derived on the basis of bootstrap techniques, does not need to assume normality or symmetry in the data, and therefore, it is highly appropriate to describe the circadian pattern of blood pressure variability. Results not only reflect expected changes in the tolerance limits as a function of gestational age, but also upper limits markedly below the thresholds currently used for diagnosing hypertension in pregnancy. The use of these time-qualified tolerance limits for the computation of a hyperbaric index as a measure of BP excess has already been show to provide high sensitivity and specificity in the early identification of gestational hypertension and preeclampsia.

Should ambulatory monitoring replace casual blood pressure measurement as the “gold standard” in the diagnosis of gestational hypertension?

Should ambulatory monitoring replace casual blood pressure measurement as the “gold standard” in the diagnosis of gestational hypertension?

Blood pressure patterns in normal pregnancy, gestational hypertension, and preeclampsia.

With the aim to describe the daily pattern of blood pressure during the trimesters of pregnancy in clinically healthy women as well as in pregnant women who developed gestational hypertension or preeclampsia, we analyzed 1494 blood pressure series systematically sampled by ambulatory monitoring for 48 hours every 4 weeks after the first obstetric visit in 124 women with uncomplicated pregnancies, 55 with gestational hypertension, and 23 with a final diagnosis of preeclampsia. The circadian pattern of blood pressure variation for each group and trimester of gestation was established by population multiple-component analysis. A highly statistically significant circadian pattern represented by a linear model that includes components with periods of 24 and 12 hours is demonstrated for systolic and diastolic blood pressure for all groups of pregnant women in all trimesters (P:<0.001 in all cases). The differences in circadian rhythm-adjusted mean between complicated and uncomplicated pregnancies are highly statistically significant in all trimesters (always P:<0.001). There is also a statistically significant difference in circadian amplitude (extent of daily change) of blood pressure between healthy and complicated pregnancies in all trimesters (always P:<0.004). Results further indicate similar circadian characteristics between women who later developed gestational hypertension or preeclampsia in the first trimester of pregnancy. The difference between these 2 groups in circadian mean is statistically significant in the second trimester for systolic (P:=0.022) but not for diastolic blood pressure (P:=0.986). In the third trimester, the difference in circadian mean is highly statistically significant for both variables (P:<0.001). The differences in blood pressure between healthy and complicated pregnancies can be observed as early as in the first trimester of pregnancy. Those highly significant differences are found when both systolic and diastolic blood pressure for women with a later diagnosis of gestational hypertension or preeclampsia are well within the accepted normal physiological range of blood pressure variability. These differing changes in the circadian pattern of blood pressure with advancing gestational age between healthy and complicated pregnancies offer new end points that may lead to an early identification of hypertensive complications in pregnancy as well as to the establishment of prophylactic intervention.

Does Gestational Hypertension Become Pre-Eclampsia?

Saudan, Patrick; Brown, Mark A.; Buddle, Megan L.; Jones, Michael Author Information

Does gestational hypertension become pre-eclampsia?

To determine the likelihood of progression from gestational hypertension (GH) to pre-eclampsia (PE) in hypertensive pregnant women and whether this change can be identified in advance by available clinical and laboratory measures. A retrospective analysis and a prospective study. St George Hospital, Sydney, a teaching hospital of the University of New South Wales delivering 2500 women per year. Eight hundred and forty-five women with new hypertension in the second half of pregnancy, managed by a uniform protocol (661 in the retrospective analysis, 184 in the prospective study). Clinical and laboratory data at initial presentation were compared among women with GH who developed PE and those who remained with a diagnosis of GH until delivery. Data predictive for progression from GH to PE were analysed by logistic regression analysis. Progression from GH to PE. In the retrospective analysis, 416 women initially presented as having GH and 62 (15%) progressed to PE. In the prospective study, 112 women initially presented with GH and 29 (26%) progressed to PE, giving an overall progression of 17%. In both studies, women who developed PE from GH presented earlier than those who remained with GH until delivery. In multiple logistic regression analyses prior miscarriage and early gestation at presentation were associated with increased likelihood of progressing from GH to PE. Approximately 15-25% of women initially diagnosed with GH will develop PE and this is more likely with earlier presentation or if the woman has had a prior miscarriage. Women with gestational hypertension diagnosed after 36 weeks of gestation have only about 10% risk of developing PE. These data should help stratify the risks of mildly hypertensive pregnant women being managed as outpatients in their third trimester.

Circadian blood pressure variability in healthy and complicated pregnancies.

With the aim to describe the circadian pattern of noninvasive ambulatorily monitored blood pressure during the trimesters of pregnancy in clinically healthy women as well as in pregnant women who developed gestational hypertension or preeclampsia, we analyzed 759 blood pressure series sampled by ambulatory monitoring for about 48 hours every 4 weeks after the first obstetric visit in 71 women with uncomplicated pregnancies, 28 with gestational hypertension, and 14 with preeclampsia. The circadian pattern of blood pressure variation for each group (complicated versus uncomplicated pregnancies) and trimester of gestation was established by linear least-squares methods. A highly statistically circadian pattern is demonstrated for systolic and diastolic blood pressure for both groups of pregnant women in all trimesters (P<.001 in all cases). Blood pressure decreases from the first trimester to the second and rises again in the third for healthy pregnant women. For women who developed gestational hypertension or preeclampsia, blood pressure is stable during the first half of pregnancy and then continuously increases until delivery. The differences in circadian rhythm-adjusted mean between complicated and uncomplicated pregnancies are highly statistically significant in all trimesters (always P<.001). This study confirms and extends to ambulatory everyday life conditions the predictable circadian variability in blood pressure during gestation. The differences in blood pressure between healthy and complicated pregnancies can be observed as early as the first trimester of pregnancy. Those differences are found when both systolic and diastolic blood pressures for women with a later diagnosis of gestational hypertension or preeclampsia are well within the accepted normal physiological range of blood pressure variability.

A prospective controlled five-year follow-up study of primiparas with gestational hypertension.

Primiparas with hypertension first recognized in pregnancy and an age- and parity-matched control group, normotensive throughout pregnancy, were monitored during 5-6 years with blood pressure recordings performed in a standardized way. At the end of the study period, 21 out of 49 women with hypertension in pregnancy had developed hypertension requiring therapy or borderline hypertension, compared with 2 women in the control group who had developed borderline hypertension. Therapy was required in 7 of the women. Factors associated with increased risk of developing hypertension were gestational week at diagnosis of gestational hypertension, 1st diastolic blood pressure during follow-up, family history, smoking, and age.