Validation of the SpaceLabs 90207 ambulatory blood pressure monitor for use in pregnancy

Cardiac Remodeling After Hypertensive Pregnancy Following Physician-Optimized Blood Pressure Self-Management: The POP-HT Randomized Clinical Trial Imaging Substudy

BACKGROUND

Hypertensive pregnancy disorders are associated with adverse cardiac remodeling, which can fail to reverse in the postpartum period in some women. The Physician-Optimized Postpartum Hypertension Treatment trial demonstrated that improved blood pressure control while the cardiovascular system recovers postpartum associates with persistently reduced blood pressure. We now report the effect on cardiac remodeling.

METHODS

In this prospective, randomized, open-label, blinded end point trial, in a single UK hospital, 220 women were randomly assigned 1:1 to self-monitoring with research physician-optimized antihypertensive titration or usual postnatal care from a primary care physician and midwife. Participants were 18 years of age or older, with preeclampsia or gestational hypertension, requiring antihypertensives on hospital discharge postnatally. Prespecified secondary cardiac imaging outcomes were recorded by echocardiography around delivery, and again at blood pressure primary outcome assessment, around 9 months postpartum, when cardiovascular magnetic resonance was also performed.

RESULTS

A total of 187 women (101 intervention; 86 usual care) underwent echocardiography at baseline and follow-up, at a mean 258±14.6 days postpartum, of which 174 (93 intervention; 81 usual care) also had cardiovascular magnetic resonance at follow-up. Relative wall thickness by echocardiography was 0.06 (95% CI, 0.07-0.05; P<0.001) lower in the intervention group between baseline and follow-up, and cardiovascular magnetic resonance at follow-up demonstrated a lower left ventricular mass (-6.37 g/m2; 95% CI, -7.99 to -4.74; P<0.001), end-diastolic volume (-3.87 mL/m2; 95% CI, -6.77 to -0.98; P=0.009), and end-systolic volume (-3.25 mL/m2; 95% CI, 4.87 to -1.63; P<0.001) and higher left and right ventricular ejection fraction by 2.6% (95% CI, 1.3-3.9; P<0.001) and 2.8% (95% CI, 1.4-4.1; P<0.001), respectively. Echocardiography-assessed left ventricular diastolic function demonstrated a mean difference in average E/E' of 0.52 (95% CI, -0.97 to -0.07; P=0.024) and a reduction in left atrial volumes of -4.33 mL/m2 (95% CI, -5.52 to -3.21; P<0.001) between baseline and follow-up when adjusted for baseline differences in measures.

CONCLUSIONS

Short-term postnatal optimization of blood pressure control after hypertensive pregnancy, through self-monitoring and physician-guided antihypertensive titration, associates with long-term changes in cardiovascular structure and function, in a pattern associated with more favorable cardiovascular outcomes.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04273854.

Setting and techniques for monitoring blood pressure during pregnancy

BACKGROUND

Regular blood pressure (BP) measurement is crucial for the diagnosis and management of hypertensive disorders in pregnancy, such as pre-eclampsia. BP can be measured in various settings, such as conventional clinics or self-measurement at home, and with different techniques, such as using auscultatory or automated BP devices. It is important to understand the impact of different settings and techniques of BP measurement on important outcomes for pregnant women.

OBJECTIVES

To assess the effects of setting and technique of BP measurement for diagnosing hypertensive disorders in pregnancy on subsequent maternal and perinatal outcomes, women's quality of life, or use of health service resources.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) on 22 April 2020, and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) involving pregnant women, using validated BP devices in different settings or using different techniques.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data, assessed risk of bias, and used the GRADE approach to assess the certainty of the evidence.

MAIN RESULTS

Of the 21 identified studies, we included three, and excluded 11; seven were ongoing. Of the three included RCTs (536,607 women), one was a cluster-RCT, with a substantially higher number of participants (536,233 deliveries) than the other two trials, but did not provide data for most of our outcomes. We generally judged the included studies at low risk of bias, however, the certainty of the evidence was low, due to indirectness and imprecision. Meta-analysis was not possible because each study investigated a different comparison. None of the included studies reported our primary outcome of systolic BP greater than or equal to 150 mmHg. None of the studies reported any of these important secondary outcomes: antenatal hospital admissions, neonatal unit length of stay, or neonatal endotracheal intubation and use of mechanical ventilation. Setting of BP measurement: self-measurement versus conventional clinic measurement (one study, 154 women) There were no maternal deaths in either the self-monitoring group or the usual care group. The study did not report perinatal mortality. Self-monitoring may lead to slightly more diagnoses of pre-eclampsia compared with usual care (risk ratio (RR) 1.49, 95% confidence interval (CI) 0.87 to 2.54; 154 women; 1 study; low-certainty evidence) but the wide 95% CI is consistent with possible benefit and possible harm. Self-monitoring may have little to no effect on the likelihood of induction of labour compared with usual care (RR 1.09, 95% CI 0.82 to 1.45; 154 women; 1 study; low-certainty evidence). We are uncertain if self-monitoring BP has any effect on maternal admission to intensive care (RR 1.54, 95% CI 0.06 to 37.25; 154 women; 1 study; low-certainty evidence), stillbirth (RR 2.57, 95% CI 0.13 to 52.63; 154 women; 1 study; low-certainty evidence), neonatal death (RR 1.54, 95% CI 0.06 to 37.25; 154 women; 1 study; low-certainty evidence) or preterm birth (RR 1.15, 95% CI 0.37 to 3.55; 154 women; 1 study; low-certainty evidence), compared with usual care because the certainty of evidence is low and the 95% CI is consistent with appreciable harms and appreciable benefits. Self-monitoring may lead to slightly more neonatal unit admissions compared with usual care (RR 1.53, 95% CI 0.65 to 3.62; 154 women; 1 study; low-certainty evidence) but the wide 95% CI includes the possibility of slightly fewer admissions with self-monitoring. Technique of BP measurement: Korotkoff phase IV (K4, muffling sound) versus Korotkoff phase V (K5, disappearance of sound) to represent diastolic BP (one study, 220 women) There were no maternal deaths in either the K4 or K5 group. There may be little to no difference in the diagnosis of pre-eclampsia between using K4 or K5 for diastolic BP (RR 1.16; 95% CI 0.89 to 1.49; 1 study; 220 women; low-certainty evidence), since the wide 95% CI includes the possibility of more diagnoses with K4. We are uncertain if there is a difference in perinatal mortality between the groups because the quality of evidence is low and the 95% CI is consistent with appreciable harm and appreciable benefit (RR 1.14, 95% CI 0.16 to 7.92; 1 study, 220 women; low-certainty evidence). The trial did not report data on maternal admission to intensive care, induction of labour, stillbirth, neonatal death, preterm birth, or neonatal unit admissions. Technique of BP measurement: CRADLE intervention (CRADLE device, a semi-automated BP monitor with additional features, and an education package) versus usual care (one study, 536,233 deliveries) There may be little to no difference between the use of the CRADLE device and usual care in the number of maternal deaths (adjusted RR 0.80, 95% CI 0.30 to 2.11; 536,233 women; 1 study; low-certainty evidence), but the 95% CI is consistent with appreciable harm and appreciable benefit. The trial did not report pre-eclampsia, induction of labour, perinatal mortality, preterm birth, or neonatal unit admissions. Maternal admission to intensive care and perinatal outcomes (stillbirths and neonatal deaths) were only collected for a small proportion of the women, identified by an outcome not by baseline characteristics, thereby breaking the random allocation. Therefore, any differences between the groups could not be attributed to the intervention, and we did not extract data for these outcomes.

AUTHORS' CONCLUSIONS

The benefit, if any, of self-monitoring BP in hypertensive pregnancies remains uncertain, as the evidence is limited to one feasibility study. Current practice of using K5 to measure diastolic BP is supported for women with pregnancy hypertension. The benefit, if any, of using the CRADLE device to measure BP in pregnancy remains uncertain, due to the limitations and instability of the trial study design.

A randomized-controlled trial to assess the effect of ibuprofen on postpartum blood pressure in women with hypertensive disorders of pregnancy

OBJECTIVES

To test the hypothesis that ibuprofen is equivalent to acetaminophen in its effect on postpartum blood pressure in women with gestational hypertension or preeclampsia without severe features.

STUDY DESIGN

Single-center randomized, crossover, equivalence trial among women with hypertensive disorders of pregnancy without severe features after vaginal delivery. Participants were assigned in a double-blind fashion to ibuprofen 600 mg or acetaminophen 650 mg every 6 h for 24 h followed by crossover to the other drug. We assessed clinical blood pressures and ambulatory blood pressure monitor measurements. Intention-to-treat analyses were performed using a linear mixed model adjusted for time period.

MAIN OUTCOME MEASURES

The mean difference in systolic blood pressure through 24 h of drug exposure with an equivalence margin of 10 mmHg.

RESULTS

Of 185 screened women, 74 enrolled prior to delivery. Forty-three women remained eligible and were randomized to ibuprofen first (n = 20, 46.5%) or acetaminophen first (n = 23, 53.5%). A total of 37 women (86.0%) received study drug (ibuprofen first n = 19, acetaminophen first n = 18). Most participants were white (91.9%) and had gestational hypertension (86.5%); mean (SD) age was 31.0 (6.5) years. The mean adjusted difference in systolic blood pressure was 1.0 mmHg (95% CI, -3.7 to 5.7 mmHg), which was within the equivalence margin. A linear mixed model did not demonstrate a main effect of group assignment, nor did it show an interaction effect with time period.

CONCLUSIONS

Among women with gestational hypertension and preeclampsia without severe features, ibuprofen is an equally safe option as acetaminophen with respect to postpartum blood pressure concerns.

Accuracy of Blood Pressure Measurement Devices in Pregnancy: A Systematic Review of Validation Studies

The accurate measurement of blood pressure (BP) in pregnancy is essential to guide medical decision making that affects both mother and fetus. The aim of this systematic review was to determine the accuracy of ambulatory, home, and clinic BP measurement devices in pregnant women. We searched Ovid MEDLINE, The Cochrane Library, EMBASE, CINAHL EBSCO, ClinicalTrials.gov, International Clinical Trials Registry Platform, and dabl from inception through August 3, 2017 for articles that assessed the validity of an upper arm BP measurement device against a mercury sphygmomanometer in pregnant women. Two independent investigators determined eligibility, extracted data, and adjudicated protocol violations. From 1798 potential articles identified, 41, that assessed 28 devices, met the inclusion criteria. Most articles (n=32) followed a standard or modified American National Standards Institute/Association for the Advancement of Medical Instrumentation/International Organization for Standardization, British Hypertension Society, or European Society of Hypertension validation protocol. Several articles described the results of validation studies performed on >1 device (n=7) or in >1 population of pregnant women (n=12), comprising 64 pairwise validity assessments. The device was validated in 61% (32 of 52) of studies which used a standard or modified protocol. Only 34% (11 of 32) of the studies wherein the device was successfully validated were performed without a protocol violation. Given the implications of inaccurate BP measurement in pregnant women, healthcare providers should be aware of and try to use the BP measurement devices which have been properly validated in this population.

A randomized trial of ambulatory blood pressure monitoring versus clinical blood pressure measurement in the management of hypertension in pregnancy. A feasibility study

To assess the feasibility of a prospective randomised trial of ambulatory blood pressure monitoring (ABPM) versus clinic blood pressure (CBP) readings for managing pregnancy hypertension. The primary outcome measure was admission to hospital. The secondary measures were number of antenatal attendances, use of anti-hypertensive drugs and duration of hospital stay. In general, there were no statistical differences between the two groups including the primary outcome, the rate of hospital admission p=0.76. 89% of participants would undergo ABPM in future pregnancies. A randomised trial of ABPM in pregnancy using this methodology is feasible and acceptable to pregnant women.

Ambulatory monitoring demonstrates an acute association between cookstove-related carbon monoxide and blood pressure in a Ghanaian cohort

BACKGROUND

Repeated exposure to household air pollution may intermittently raise blood pressure (BP) and affect cardiovascular outcomes. We investigated whether hourly carbon monoxide (CO) exposures were associated with acute increases in ambulatory blood pressure (ABP); and secondarily, if switching to an improved cookstove was associated with BP changes. We also evaluated the feasibility of using 24-h ambulatory blood pressure monitoring (ABPM) in a cohort of pregnant women in Ghana.

METHODS

Participants were 44 women enrolled in the Ghana Randomized Air Pollution and Health Study (GRAPHS). For 27 of the women, BP was measured using 24-h ABPM; home blood pressure monitoring (HBPM) was used to measure BP in the remaining 17 women. Personal CO exposure monitoring was conducted alongside the BP monitoring.

RESULTS

ABPM revealed that peak CO exposure (defined as ≥4.1 ppm) in the 2 hours prior to BP measurement was associated with elevations in hourly systolic BP (4.3 mmHg [95% CI: 1.1, 7.4]) and diastolic BP (4.5 mmHg [95% CI: 1.9, 7.2]), as compared to BP following lower CO exposures. Women receiving improved cookstoves had lower post-intervention SBP (within-subject change in SBP of -2.1 mmHg [95% CI: -6.6, 2.4] as compared to control), though this result did not reach statistical significance. 98.1% of expected 24-h ABPM sessions were successfully completed, with 92.5% of them valid according to internationally defined criteria.

CONCLUSIONS

We demonstrate an association between acute exposure to carbon monoxide and transient increases in BP in a West African setting. ABPM shows promise as an outcome measure for assessing cardiovascular health benefits of cookstove interventions.

TRIAL REGISTRATION

The GRAPHS trial was registered with clinicaltrials.gov on 13 April 2011 with the identifier NCT01335490 .

Awaiting blood pressure stabilization in ambulatory pregnant women: is 5 minutes sufficient?

OBJECTIVE

Current recommendations for timing of blood pressure measurement in ambulatory pregnant women vary and are based on studies in the nonpregnant population. The objective of this study was to determine if there is a difference in systolic blood pressure (SBP) and diastolic blood pressure (DBP) between minute-5 and minute-10.

METHODS

A prospective study was conducted at our prenatal care clinics. Participants had their blood pressure measured upon sitting and every 5 minutes for 15 minutes. Initial SBP and DBP were compared to measurements at each time point. Additionally, the SBP and DBP at minute-5 were compared to minute-10. All statistical tests were two-sided.

RESULTS

Data from 400 patients were analyzed. Of these, 34.0% were in the first, 30.7% were in the second trimester, and 35.2% were in the third trimester. In each trimester, there was a significant difference in the SBP and DBP at minute-5 compared to minute-0. At minute-10 compared to minute-5, there was no further drop for all trimesters, except for a small drop in DBP in the second trimester (-1.3 ± 6.0, p = 0.012).

CONCLUSION

In an ambulatory setting, 5 minutes after sitting appears to be an appropriate time point to measure blood pressure in pregnancy.

The use of ambulatory blood pressure measurement

Measurement of ambulatory blood pressure is recommended by the National Institute for Health and Care Excellence guidelines to confirm the diagnosis of hypertension in the UK. This article describes the use of ambulatory devices, and discusses the benefits and disadvantages of their use in clinical practice.

Association of three different techniques to measure blood pressure in the first trimester with the development of hypertensive disorders of pregnancy

OBJECTIVE

It is not known whether automated devices for measuring blood pressure perform better than conventional sphygmomanometry in predicting preeclampsia. This study compares two different automated devices with conventional sphygmomanometry for their association with development of preeclampsia or gestational hypertension.

DESIGN

Prospective observational cohort study.

SETTING

University hospital, Amsterdam, the Netherlands.

POPULATION

289 healthy normotensive women of whom 235 were nulliparous and 44 parous with preeclampsia in a previous pregnancy.

METHODS

At 8-11 weeks of pregnancy, blood pressure was measured with two different automated devices (continuous finger arterial pressure waveform registration and ambulatory blood pressure monitoring) and with conventional sphygmomanometry.

MAIN OUTCOME MEASURES

Preeclampsia and gestational hypertension.

RESULTS

Blood pressure in the first trimester, as measured with all three methods, was significantly higher in women who developed preeclampsia or gestational hypertension. After adjustment for previous preeclampsia, the point estimate of the odds ratios for association with later preeclampsia for both automated devices were comparable and higher than for conventional sphygmomanometry; however, differences were not statistically significant. The odds ratio (95% confidence intervals) for every 1 mmHg pressure increase of mean arterial pressure was 1.08 (1.02-1.15) for sphygmomanometry, 1.17 (1.09-1.27) for finger arterial pressure waveform registration, and 1.17 (1.07-1.27) for ambulatory blood pressure monitoring. Results were comparable if preeclampsia and gestational hypertension were analyzed together.

CONCLUSION

Blood pressure in the first trimester was associated with the development of hypertensive disorders of pregnancy. No significant differences were found between measurements by automatic devices compared with conventional sphygmomanometry.

Method of mean value calculation as an additional source of variability in ambulatory blood pressure measurement

BACKGROUND

There is no consensus on how the summary mean blood pressure (BP) values should be calculated in ambulatory BP (ABP) monitoring. We report the absence of agreement between two common methods of calculation, either using the arithmetic mean of all valid individual measurements, or the average of hourly means.

METHODS

ABP recordings were made with SpaceLabs 90207 monitors. The means of hourly means, as reported by SpaceLabs 92506 software, were compared to arithmetic means calculated independently after raw data extraction. A total of 422 ABP recordings (n = 134 for normotensive subjects and n = 288 for hypertensive patients) were eligible for comparison. Agreement between both methods was assessed according to the Bland-Altman method.

RESULTS

Mean 24-h systolic BP (SBP) was significantly lower when calculated by the hourly mean method in both normotensive subjects (-0.9 mm Hg (95% confidence interval (95% CI): -1.0 to -0.8); limits of agreement: -2.2 to +0.4 mm Hg) and hypertensive patients (-1.0 mm Hg (95% CI: -1.2 to -0.9); limits of agreement: -3.7 to +1.6 mm Hg). In hypertensive patients, daytime SBP/diastolic BP was slightly higher with the hourly mean method (0.4 mm Hg (95% CI: +0.3 to +0.5)/+0.4 mm Hg (95% CI: +0.3 to +0.4)) than with the arithmetic mean method. Although small, these differences in daytime BP resulted in misdiagnosis of uncontrolled hypertension in eight (2.8%) recordings.

CONCLUSION

Significant differences exist between the mean of hourly means and arithmetic means methods, especially for 24-h BP. For daytime BP, the difference is small, but nevertheless results in the lack of agreement between the two methods used to diagnose uncontrolled hypertension.

Twenty-four-hour and conventional blood pressure components and risk of preterm delivery or neonatal complications in gestational hypertension

Gestational hypertension is a recognized risk factor for the development of complications during pregnancy. The present study retrospectively assessed the respective values of blood pressure components derived from conventional and 24-h recordings (ABPM) as predictors of premature delivery in women with gestational hypertension based on office readings from 26th week of gestation onwards. Blood pressures were measured conventionally and over 24 h. Standard medical and obstetric history, and standard laboratory work-up were taken into account. The mean (+/- standard deviation, SD) age of 123 women was 29 +/- 6 years. Current pregnancy was, on average, the second. The conventional systolic (SBP)/diastolic (DBP) blood pressure averaged 140 +/- 19/92 +/- 14 mmHg, and pulse pressure (PP) and mean arterial pressure (MBP) averaged 48 +/- 10 and 108 +/- 15 mmHg. The corresponding values derived from ABPM were 135 +/- 16/90 +/- 11, 47 +/- 9 and 105 +/- 12 mmHg. The 24-h blood pressures had better prognostic value than the conventional blood pressures. The 24-h SBP predicted risk of premature delivery and was inversely related to the duration of pregnancy and birth weight. After the exclusion of 41 women with white-coat hypertension, the highest predictive value was associated with PP. PP wider by 1SD was associated with 66% higher risk of premature delivery, and was associated with shortening of pregnancy by 2 weeks and 400 g lower birth weight, even after adjustment for SBP. In conclusion, ABPM is superior to conventional blood pressure measurements in predicting adverse outcome of pregnancy. Twenty-four-hour PP, of all classic indices, seems to be most closely related to increase of that risk.

Predicting Transformation from Gestational Hypertension to Preeclampsia in Clinical Practice: A Possible Role for 24 Hour Ambulatory Blood Pressure Monitoring

OBJECTIVE

To identify parameters that may assist clinicians in predicting which women will develop preeclampsia (PE) after initially presenting with gestational hypertension (GH).

METHODS

118 women were recruited to the study with GH or PE. They were divided into three groups based on their diagnosis at delivery- (1) GH, (2) PE from the time of presentation, (3) those with an initial diagnosis of GH who progressed to PE. Women underwent 24 hour ambulatory blood pressure monitoring (ABPM) and had serum estrogen, progesterone, beta-HCG, leptin and adiponectin measured as possible predictors of transformation of GH to PE.

RESULTS

Women who presented with GH, and progressed to PE, presented four weeks earlier (33 vs 37 weeks, p < 0.001) than those who did not progress. Women with PE, either as their initial diagnosis or after progression from GH, were delivered earlier (p < 0.001) and had more small for gestational age (SGA) babies than women with GH at delivery (p < 0.05). Those who developed PE after presenting with GH generally had higher blood pressures than those who remained as GH, significant for awake and 24 hour systolic blood pressures (p < 0.05). beta-HCG, estrogen, progesterone or leptin values were similar across the groups. Adiponectin was higher in women with established PE at presentation compared to women with GH (p = 0.02) but adiponectin failed to discriminate those women with an initial diagnosis of GH who progressed to PE.

CONCLUSION

24 hr ABPM may provide a non-invasive method of identifying this 'at risk' GH population, particularly in the case of early presentation.

Increase in Systolic Blood Pressure of ≥ 30 mm Hg and/or Diastolic Blood Pressure of ≥ 15 mm Hg During Pregnancy: Is It Pathologic?

OBJECTIVE

To determine whether a rise in systolic blood pressure (SBP) > or = 30 mm Hg and/or diastolic blood pressure (DBP) > or = 15 mm Hg in the absence of hypertension during pregnancy is associated with adverse pregnancy outcomes.

METHOD

We conducted a retrospective, longitudinal study of 1,498 pregnant women without hypertension or proteinuria in the first trimester. The blood pressure levels measured during the first (7.8 +/- 2.3 weeks), second (20.7 +/- 1.2 weeks), and third trimesters (38.6 +/- 1.5 weeks) were analyzed. The perinatal outcome was compared between women who exhibited a rise in SBP > or = 30 mm Hg and/or DBP > or = 15 mm Hg during pregnancy (large Delta BP group) and women who did not (small Delta BP group) using one way analysis of variance, chi-square test, or Fisher's exact test. The contribution of gestational hypertension and a large Delta BP to the development of adverse pregnancy outcomes was evaluated using multivariate logistic regression analysis.

RESULTS

Of 1441 women who remained normotensive (SBP < 140 mm Hg and DBP < 90 mm Hg) during pregnancy, 238 (16.5%) and 1,203 (83.5%) belonged to the large Delta BP and small Delta BP groups, respectively. There were no significant differences between the two groups in the occurrence rate of gestational proteinuria, preterm deliveries, low-birth-weight infants, or small-for-gestational age infants. A large Delta BP was not a risk factor in itself for the occurrence of gestational proteinuria or small-for-gestational age infants after controlling for the effect of gestational hypertension.

CONCLUSION

A rise in SBP > or = 30 mm Hg and/or DBP > or = 15 mm Hg is not a risk factor of adverse outcome among women who remain normotensive during pregnancy.

Circadian Blood Pressure Variability in Normotensive Pregnant Women as a Function of Parity, Maternal Age, and Stage of Gestation

Studies based on conventional office blood pressure (BP) measurements concluded that both maternal age and parity have significant effects on BP during pregnancy. Previous results have also indicated predictable trends of BP variability with gestational age. Accordingly, we have evaluated possible differences in the circadian pattern of ambulatory BP as a function of parity, maternal age, and stage of gestation in normotensive women who were systematically studied by ambulatory BP monitoring during their pregnancies. We analyzed 1408 BP profiles obtained from 126 nulliparous and 109 multiparous pregnant women sampled for 48 consecutive h every 4 weeks from the first obstetric visit (usually within the first trimester of pregnancy) until delivery. Data were divided for comparative analysis according to parity (nulliparous versus multiparous), age (< or = 25, 26-30, 31-35, and > or = 36 yrs), and trimester of gestation. Circadian BP parameters established by population multiple-components analysis were compared between groups using a nonparametric test. A highly statistically significant circadian pattern described by a model that includes components with periods of 24 and 12h is demonstrated for systolic and diastolic BP for all groups of pregnant women in all trimesters (always p < 0.001). There was no significant difference in the 24h mean among groups divided by parity at any age or stage of pregnancy. A trend of increasing BP with age was found for diastolic but not for systolic BP. Although statistically significant, differences in the 24h mean of diastolic BP among groups divided by age were always less than 2 mm Hg. Data obtained from systematic ambulatory monitoring in normotensive pregnant women indicate the lack of differences in BP according to parity. The small, although significant, increase in diastolic BP with age may have scarce influence in the proper identification of women with gestational hypertension. Reference thresholds for BP to be used in the early identification of hypertensive complications in pregnancy could thus be developed as a function of the rest-activity cycle and gestational age only, and independently of parity or maternal age.

Physiological changes of pregnancy and monitoring

Advances in medical care have led to increasing numbers of complex, high-risk obstetric patients. Specialist training and a sound knowledge of normal maternal physiology are essential to optimize outcomes. One of the earliest observed changes is peripheral vasodilatation; this causes a fall in systemic vascular resistance and triggers physiological changes in the cardiovascular and renal systems, with 40-50% increases in cardiac output and glomerular filtration rates. Safety concerns over Swan Ganz catheters have driven the increasing interest in alternative techniques, such as echocardiography, thoracic bioimpedance and pulse contour analysis, although their exact roles in future obstetric high-dependency care have yet to be established. Analysis of arterial blood gases is fundamental to the management of sick patients, and correct interpretation can be aided by a systematic approach. Observation charts are almost ubiquitous in all aspects of medicine, but little evidence exists to support their use in the high-dependency setting.

Diurnal blood pressure variation in the evaluation of early onset severe pre-eclampsia

OBJECTIVE

To study the association between diurnal variation in blood pressure, the mean daily blood pressure and various complications of pregnancy in patients presenting with severe pre-eclampsia before 34 weeks' gestation.

STUDY DESIGN

Forty-four women presenting to a tertiary hospital in South Africa with severe pre-eclampsia between 28 and 34 weeks' gestation were managed expectantly for at least 8 days. We measured maternal blood pressure every 30 min with the pregnancy validated Spacelabs 90209 automated blood pressure monitor for 24h periods on alternative days. The mean 24-h diastolic blood pressure measurement, the mean diastolic blood pressure for daytime and nighttime, the day-night blood pressure difference and the night-day ratio were compared with the occurrence of abruptio placentae, gestational age at delivery, neonatal intensive care unit admission, birth weight, abnormal umbilical artery Doppler FVW and reason for delivery.

RESULTS

One hundred and seventy-six 24-h studies were analyzed. The day-night blood pressure difference decreased with increasing mean diastolic blood pressure (r=-0.323, p<0.0001). A combination of normal mean diastolic blood pressure and normal day-night blood pressure difference was associated with increased gestational age and lower caesarean section rates.

CONCLUSION

The combination of mean diastolic blood pressure and day-night blood pressure difference may be a supplementary measurement of disease severity in early onset severe pre-eclampsia and seems to be of prognostic value.

Prediction of pre-eclampsia in early pregnancy

Pre-eclampsia is a multisystem disorder of pregnancy, usually characterized by the appearance of high blood pressure and the excretion of protein in the urine of a previously healthy woman. Symptoms and signs vary in intensity from woman to woman; from a borderline rise in blood pressure, to convulsions (eclampsia), stroke and death. The disease remits following removal of the placenta and so the mainstay of current treatment is timely delivery. A pathophysiological framework of the disease has been established, beginning with failures in placental development, inducing oxidative stress and release of compounds that lead to endothelial activation, vasoconstriction and glomerular endotheliosis. A combination of epidemiological, biophysical and biochemical tests now allow most patients at-risk to be identified by midpregnancy, whilst minimizing false-positive prediction. It is hoped that earlier classification of patients at-risk of the disease, on the basis of pathophysiological changes, will enable specific therapies to be developed targeting these changes.

Water immersion in preeclampsia

OBJECTIVE

Preeclampsia is associated with profound vasoconstriction in most organ systems and reduced plasma volume. Because water immersion produces a marked central redistribution of blood volume and suppresses the renin-angiotensin system response and sympathetic activity, we hypothesized that water immersion might be useful in the treatment of preeclampsia.

STUDY DESIGN

The effects of thermoneutral water immersion for 3 hours on central and peripheral hemodynamics were evaluated in 7 preeclamptic patients, 7 normal pregnant control patients, and 7 nonpregnant women. Finger plethysmography was used to determine hemodynamic measurements (cardiac output and total peripheral resistance), and forearm blood flow was measured by strain gauge plethysmography. Postischemic hyperemia was used to determine endothelium-dependent vasodilation. Analysis was by analysis of variance for repeated measurements.

RESULTS

During water immersion cardiac output increased while diastolic blood pressure and heart rate decreased, although systolic blood pressure remained unchanged in each group. Forearm blood flow increased significantly in the normal pregnant and preeclamptic subjects. Total peripheral resistance decreased in all groups, but values in preeclamptic patients remained above those of normotensive pregnant women. Water immersion had no effect on endothelium-dependent vasodilation in the preeclamptic group, and most hemodynamic changes that were observed reversed to baseline within 2 hours of completion of the procedure.

CONCLUSION

Although water immersion results in hemodynamic alterations in a manner that is theoretically therapeutic for women with preeclampsia, the effect was limited and short-lived. In addition water immersion had no effect on endothelium-dependent vasodilation in women with preeclampsia. The therapeutic potential for water immersion in preeclampsia appears to be limited.

Preterm delivery in normoalbuminuric, diabetic women without preeclampsia: The role of metabolic control

OBJECTIVE

The aim of this study was to examine the importance of glycemic regulation on the risk of preterm delivery in women with normoalbuminuria and no preeclampsia later in pregnancy.

STUDY DESIGN AND METHODS

A prospective study of 71 women with type 1 diabetes mellitus where complete data were collected on HbA1c, insulin dose, and albumin excretion rate from week 12 and every second week hereafter. Fundus photography was performed and diurnal blood pressure measured three times during pregnancy.

RESULTS

The preterm rate was 23% and women delivering preterm showed higher HbA1c throughout pregnancy. At regression analysis HbA1c was the strongest predictor for preterm delivery from week 6 to 32, also when including insulin dose, BMI, age, duration of diabetes, and diurnal blood pressure. The risk of delivering preterm was more than 40% when HbA1c was above 7.7% in week 8. Diurnal blood pressure was not found associated with preterm delivery.

CONCLUSION

The quality of glycemic regulation in the early and mid-pregnancy is a major, independent risk factor for preterm delivery in normoalbuminuric diabetic women without preeclampsia.

Circadian rhythm of maternal blood pressure and fetal growth

This study aimed at examining any relation between the circadian variation in blood pressure (BP) in human pregnancy and fetal growth. A prospective study included 52 pregnant women monitored during the third trimester of pregnancy. There were 33 uncomplicated pregnancies with normal fetal growth (Group 1) and 19 pregnancies complicated by intrauterine growth retardation (IUGR), confirmed at birth (Group 2). Ten women (five in each group) had pregnancy-induced hypertension. All women were hospitalized and followed a similar daily routine. BP was recorded with an automatic wearable device. Measurements were obtained every 20 min for 24 +/- 1 h. BP profiles were analyzed by conventional statistical methods and by cosinor, involving the least squares fit of cosine curves with an anticipated period (24 h) to the data. BP parameters, fetal outcome, demographic and obstetric characteristics were compared between the two groups. Logistic regression and multivariate analyses were used to assess factors putatively associated with fetal outcome. The circadian amplitude of diastolic BP was found to be larger in normotensive women with IUGR. As gauged by odds ratios (OR), the circadian amplitude of diastolic BP (OR = 1.7, 95% CI: 1.1-2.8; P = 0.03) and hematocrit (OR = 1.4, 95% CI: 1.0-1.9; P = 0.04) were the only variables positively and independently associated with IUGR. In the presence of maternal hypertension, the circadian amplitude of systolic BP was negatively associated with IUGR (OR = 0.7, 95% CI: 0.5-1.0; P = 0.03). A larger circadian variation in diastolic BP, rather than a difference in the mean value of systolic or diastolic BP, was found to be statistically significantly associated with IUGR. This study adds another condition in which the circadian BP amplitude constitutes a harbinger of elevated risk, apart from an association with a shortened lifespan in the absence or presence of malignant hypertension and with an increased risk of stroke and nephropathy reported earlier.

The natural history of white coat hypertension during pregnancy

OBJECTIVE

White coat hypertension (WCH) is a common phenomenon with a long term prognosis intermediate between those with true hypertension and true normotension. The natural history of this phenomenon throughout pregnancy remains unknown. We assessed the likelihood of women with an initial diagnosis of WCH developing pre-eclampsia (PE) as their pregnancy progressed.

DESIGN

Prospective observational study.

SETTING

St George Hospital, a teaching and University hospital.

POPULATION

Two hundred and forty-one pregnant women with an early pregnancy diagnosis of essential hypertension (EH).

METHODS

Eighty-six women had this diagnosis (EH) confirmed pre-pregnancy by 24-hour ambulatory blood pressure monitoring (ABPM) or repeated automated home blood pressure (BP) self-measurement. The remaining 155 underwent 24-hour ABPM in early pregnancy to establish their diagnosis. Women found to have WCH did not receive antihypertensives during their pregnancy, whereas those with confirmed EH received oxprenolol or methyldopa. Women with WCH had repeated 24-hour ABPM and/or BP assessments in a pregnancy day assessment unit until delivery.

MAIN OUTCOME MEASURE

The development of PE in women with WCH or EH.

RESULTS

The overall prevalence of WCH was 32%. Half retained this phenomenon throughout pregnancy and had good pregnancy outcomes. Forty percent developed (benign) gestational hypertension and also had good pregnancy outcomes while 8% developed proteinuric PE, significantly fewer than in women with confirmed EH (22%), P= 0.008. No BP parameter at study entry permitted discrimination between those women with WCH who retained this phenomenon and those who developed GH or PE.

CONCLUSION

WCH is a common phenomenon in pregnant women who appear to have EH according to routine BP measurement early in pregnancy. Antihypertensives may be withheld from this group initially and they can be advised they will have better pregnancy outcomes than women with true EH. However, continued monitoring throughout pregnancy remains important to detect the small group of white coat hypertensives who develop PE.

Patient satisfaction with the SpaceLabs 90207 ambulatory blood pressure monitor in pregnancy

OBJECTIVE

The objective of this study was to evaluate the acceptability of the SpaceLabs 90207 ambulatory blood pressure monitor among pregnant women.

METHODS

Patients participating in research projects involving ambulatory blood pressure monitoring (ABPM) in pregnancy (N = 110) were asked to complete a questionnaire relating to patient satisfaction on completion of the monitoring period. The first part of the questionnaire involved rating on a visual Likert scale (0-10) whether they found the monitor heavy, noisy, cumbersome, disturbing, or embarrassing to wear. The second part of the questionnaire addressed whether cuff inflation caused significant sleep disturbance or physical discomfort.

OUTCOME MEASURES

The mean (SD) and range of the Likert scores are reported. The number of patients reporting sleep disturbance or physical discomfort was calculated. Logistic regression was used to examine which factors were significant predictors of discontinuing monitoring.

RESULTS

The mean (SD) responses measured by the Liken scores were: finding the monitor heavy 3.2 (2.3); comfortable 4.8 (2.3); straightforward to use 8.8 (1.8); cumbersome 3.8 (2.3); disturbing 4.5 (2.7); noisy 1.6 (2.2); and embarrassing to wear 1.7 (2.1). Difficulty initiating sleep was reported by 28.8% of patients, and a further 56.3% reported difficulty maintaining sleep due to the monitor. Sleep disturbance was found to be the strongest predictor [r = 0.52; OR 1.68 (1.23, 2.27), p = 0.0009] for the 15% of patients discontinuing the monitoring.

CONCLUSIONS

While pregnant women tolerate the noise, weight, inconvenience, and disturbance associated with ambulatory blood pressure monitoring (ABPM) well, sleep disturbance is a major cause of dissatisfaction and noncompliance. Future studies should evaluate critically the number of nocturnal blood pressure assessments required, and should allow for a withdrawal rate of approximately 15% when performing sample size calculations for ABPM studies in pregnancy.

Valoración prospectiva del test de tolerancia hiperbárica en el diagnóstico de hipertensión gestacional y preeclampsia

BACKGROUND AND OBJECTIVE

Recent studies have tried to overcome poor results from isolated blood pressure values in detecting hypertension in pregnancy by relying on ambulatory monitoring. Low sensitivity of the 24-hour mean has led many authors to conclude that ambulatory monitoring is not a valid approach in pregnancy. Against this background, we have evaluated prospectively the sensitivity and specificity in the diagnosis of gestational hypertension of the tolerance-hyperbaric test. This is a combined approach consisting of establishing tolerance intervals for the circadian variability of blood pressure as a function of gestational age, and then computing the hyperbaric index (area of blood pressure excess above the upper limit of the interval) by comparison of any patient's blood pressure profile with those limits.

PATIENTS AND METHOD

We studied 328 women who provided a 2014 blood pressure series. They were sampled for 48 hours once every 4 weeks from the first obstetric visit (mostly within the first trimester of gestation) until delivery. The hyperbaric index of each blood pressure series was calculated by taking into account the reference circadian tolerance limits established from a 497 series previously sampled from an independent reference group of 189 normotensive pregnant women.

RESULTS

Sensitivity of the tolerance-hyperbaric test was 91% for women sampled during the first trimester of gestation, and increased up to 99% in the third trimester. Specificity was above 99% in all trimesters. Positive and negative predictive values were above 96% in all trimesters. Moreover, the hyperbaric index provided an early identification of subsequent gestational hypertension and preeclampsia, on the average of 23 weeks prior to the clinical confirmation of the disease.

CONCLUSIONS

The tolerance-hyperbaric test represents a reproducible, stable, noninvasive, and high sensitivity test for the very early identification of subsequent gestational hypertension and preeclampsia, which can also be used as a guide for establishing prophylactic or therapeutic interventions.

Methodological and technical issues related to the diagnosis, screening, prevention, and treatment of pre-eclampsia and eclampsia

In contrast with advances made in treating or eliminating many other serious disorders, severe morbidity and mortality associated with pre-eclampsia/eclampsia remain among the leading problems that threaten safe motherhood, particularly in developing countries. This article reviews technical issues related to diagnosis, screening, prevention, and treatment of pre-eclampsia and identifies corresponding needs. The authors stress the lack of standardized definitions of pre-eclampsia and eclampsia and discuss problems in blood-pressure measurements and assessment of urinary protein. They summarize the evidence for prevention strategies and screening tests for early detection. For treatment, magnesium sulfate has been proven effective, but not widely used. The authors outline priorities for narrowing the identified gaps and emphasize the need for coordinated efforts to reduce the morbidity and mortality due to pre-eclampsia/eclampsia. They conclude that the mystery of this disease must be resolved to achieve primary prevention of it.

Reproducibility of the tolerance-hyperbaric test for diagnosing hypertension in pregnancy

BACKGROUND

The tolerance-hyperbaric test has been shown to provide a valuable approach for the prediction of the outcome of pregnancy. In this test, diagnosis of hypertension is based on the hyperbaric index (area of blood pressure excess above the upper limit of a reference threshold) calculated by comparison with a time-specified tolerance interval for the circadian variability of blood pressure.

OBJECTIVE

To evaluate prospectively the stability and reproducibility of the tolerance-hyperbaric test.

METHODS

We studied 403 women who provided 2430 blood pressure series sampled for 48 consecutive hours once every 4 weeks from the first obstetric visit (mostly within the first trimester of gestation) until delivery. Circadian 90% tolerance limits for blood pressure were established as a function of trimester of gestation from 497 series previously sampled from an independent reference group of 189 normotensive pregnant women. Diagnosis of hypertension was established in this trial for each woman in the validation sample on the highly restricted basis of presenting at least one blood pressure profile with a hyperbaric index above the threshold for diagnosis after 20 weeks of gestation.

RESULTS

Sensitivity of the tolerance-hyperbaric test was 93% for women sampled during the first trimester of gestation, and increased to 99% by the third trimester. Specificity was more than 99% in all trimesters. The positive and negative predictive values were greater than 96% in all trimesters.

CONCLUSIONS

The tolerance-hyperbaric test represents a reproducible, stable, non-invasive and high-sensitivity test for the very early identification of subsequent hypertension in pregnancy.

Validation and use of the FinometerTM for blood pressure measurement in normal, hypertensive and pre-eclamptic pregnancy

OBJECTIVE

Although a large variety of automated blood pressure devices are available, only some have been validated for use in clinical practice. The British Hypertension Society (BHS) recommends separate validation of automated devices in special subgroups, e.g. the elderly and pregnant women. The aim of this study was to compare the Finometer (FM) and the earlier validated SpaceLabs 90207 (SL) with standard auscultatory blood pressure measurements in normal, pre-eclamptic and hypertensive pregnancy, following the guidelines of the BHS and the Association for the Advancement of Medical Instrumentation (AAMI).

METHODS

The total study group consisted of 123 pregnant women, of whom were 54 normotensive, 31 pre-eclamptic and 38 hypertensive. Automated readings with the FM and SL were compared with auscultatory blood pressure measurements. Bland-Altman plots, BHS grades, mean pressure differences and 95% limits of agreement were used for analysis.

RESULTS

Bland-Altman plots showed a wide scatter of the pressure differences between auscultatory and automated measurements. FM achieved BHS grades C/D, C/B, D/D and D/D in the total, normotensive, pre-eclamptic and hypertensive group, respectively. The AAMI criteria were only met for diastolic blood pressure in the normotensive group. For SL almost identical BHS grades and 95% limits of agreement as compared to our earlier study were found.

CONCLUSIONS

The accuracy and precision of the Finometer are not sufficient for determination of absolute blood pressure levels in individual pregnant women. Our present findings on the SpaceLabs 90207 reconfirm our earlier results.

Sampling requirements for ambulatory blood pressure monitoring in the diagnosis of hypertension in pregnancy

Previous studies on ambulatory blood pressure monitoring as a potential screening test for hypertension in pregnancy have not carefully considered sampling requirements. We have examined the impact of duration and frequency of blood pressure sampling in the reproducibility of mean values in pregnancy. We analyzed 2430 blood pressure series sampled every 20 minutes during the day and every 30 minutes at night for 48 hours every 4 weeks from the first obstetric visit until delivery in 235 normotensive and 168 hypertensive pregnant women. Blood pressure series were decimated to generate shorter series with data sampled every 1, 2, 3, or 4 hours for 48 hours, as well as at the original rate for the first day. Reproducibility of mean blood pressure as well as sensitivity and specificity in the diagnosis of hypertension were compared between the original and the decimated series. Sensitivity and specificity of the 24-hour blood pressure mean are similar for the values calculated from the original series and for those obtained from shorter profiles up to data sampled every 3 hours but reduced by 5% to 12% when diagnosis is based on data sampled at 20- to 30-minute intervals for the first 24 hours. Results also indicate that the 24-hour blood pressure mean is better reproduced with data sampled at 3-hour intervals for 48 hours than by data sampled at 20- to 30-minute intervals for 1 day only. This study demonstrates that reproducibility of mean blood pressure values is more dependent on duration of sampling than on sampling rate.

[Circadian blood pressure variation in normal pregnancy, gestational hypertension, and preeclampsia]

BACKGROUND AND OBJECTIVE

Changes in circadian variation of blood pressure could be used either to predict preeclampsia or to assess its severity. With the objective of identifying potential differences in blood pressure at the early stages of pregnancy, we examined and compared the characteristics of circadian variability in blood pressure in healthy and complicated pregnant women who were systematically monitored throughout gestation.

SUBJECTS AND METHOD

We analyzed 2,014 blood pressure series sampled through ambulatory monitoring for 48 hours once every 4 weeks from the first obstetric visit until delivery. The study included 205 women with uncomplicated pregnancy, 92 with gestational hypertension and 31 with preeclampsia. The circadian pattern of blood pressure variation for each group and trimester of gestation was established by means of a population multiple-components analysis.

RESULTS

Differences in the 24-hour mean between healthy and complicated pregnancies were highly significant in all trimesters (p < 0.001), with values of 15.1 and 9.1 mmHg for systolic and diastolic blood presure, respectively, in the third trimester of pregnancy. The 24-hour mean of systolic/diastolic blood pressure for complicated pregnancies was always below 120/72 mmHg. Results further indicated similar circadian characteristics between gestational hypertension and preeclampsia in the first trimester of pregnancy. The difference between these two groups in the 24-hour mean was significant in the second trimester for systolic (3 mmHg; p = 0.002) but not diastolic blood pressure (0.9 mmHg; p = 0.230). In the third trimester, the difference between gestational hypertension and preeclampsia was significant for both variables (5.4 and 3.7 mmHg for systolic and diastolic blood pressure, respectively; p < 0.001).

CONCLUSIONS

The differences in blood pressure between healthy and complicated pregnancies, which are observed as early as the first trimester of pregnancy, are detected when both systolic and diastolic blood pressure measurements in women with a late diagnosis of gestational hypertension or preeclampsia fall within accepted ranges of normotension. These differences offer new end points that may lead to an early identification of hypertensive complications in pregnancy as well as to the establishment of prophylactic interventions.

Administration time-dependent influence of aspirin on blood pressure in pregnant women

This study prospectively investigates the potential influence of low-dose aspirin on blood pressure in pregnant women who were at a higher risk of developing preeclampsia than that of the general obstetric population and who received aspirin at different times of the day according to their rest-activity cycle. A double-blind, randomized, controlled trial was conducted in 341 pregnant women (181 primipara) randomly assigned to 1 of 6 possible groups according to treatment (either placebo or aspirin, 100 mg/day, starting at 12 to 16 weeks of gestation) and the time of treatment: on awakening (time 1), 8 hours after awakening (time 2), or before bedtime (time 3). Blood pressure was automatically monitored for 48 consecutive hours every 4 weeks from the day of recruitment until delivery, as well as at puerperium. There was no effect of aspirin on blood pressure at time 1 (compared with placebo). A blood pressure reduction was highly statistically significant when aspirin was given at time 2 and, to a greater extent, at time 3 (mean reductions of 9.7/6.5 mm Hg in 24-hour mean for systolic/diastolic blood pressure at the time of delivery as compared with placebo given at bedtime). Differences in blood pressure among women receiving aspirin at different circadian times disappeared at puerperium (P>0.096). Results indicate a highly significant effect of aspirin on blood pressure that is markedly dependent on the time of aspirin administration with respect to the rest-activity cycle. Timed use of aspirin at low dose effectively contributes to blood pressure control in women at high risk for preeclampsia.

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 mmHg 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 mmHg 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 24h 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.

The effect of hospitalisation on ambulatory blood pressure in pregnancy

METHODS

Twenty-four-hour ambulatory blood pressure monitoring was performed on 40 women (20 hypertensive, 20 normotensive) on a hospitalised and non-hospitalised day. Mean blood pressure differences were calculated for the awake, sleeping and 24-hour periods on both days.

RESULTS

Mean heart rate was higher at home (1.79, p = 0.04) than in hospital, but there were no significant differences in mean systolic (1.30 mmHg, p = 0.06), diastolic (0.78 mmHg, p = 0.21) or mean arterial blood pressure (0.81 mmHg, p = 0.19) between the hospitalised and non hospitalised day for the group overall. Nevertheless, the range of individual responses was wide (-8.5 mmHg to 15.4 mmHg mean arterial blood pressure). Hypertensive women receiving antihypertensive therapy had significantly greater differences in mean arterial blood pressure between the hospital and non-hospital day when compared to the rest of the group (5.8 mmHg, compared to 3.3 mm Hg, p = 0.02).

CONCLUSIONS

Although hospitalisation does not significantly lower blood pressure in pregnant women as a group, women receiving antihypertensive therapy demonstrate significant differences in blood pressure between hospital and home. Based on conventional blood pressure measurements alone, these women may be at risk of either under treatment, or over treatment, of blood pressure.

Prognostic value of office and ambulatory blood pressure measurements in pregnancy

With the objective to assess the prognostic value of office values as compared with ambulatory monitoring in pregnancy, we analyzed 2430 blood pressure series systematically sampled from 403 untreated pregnant women for 48 consecutive hours every 4 weeks from the first visit to the hospital until delivery. Women were divided into 5 groups: "detected" gestational hypertension, women with office blood pressures >140/90 mm Hg after 20 weeks of gestation and hyperbaric index (area of blood pressure excess above the upper limit of a time-specified tolerance interval) consistently above the threshold for diagnosing hypertension in pregnancy; "undetected" gestational hypertension, office values <140/90 mm Hg but hyperbaric index above the threshold for diagnosis; normotension, both office values and hyperbaric index below the thresholds for diagnosis; white coat hypertension, women with recorded diagnosis of gestational hypertension but hyperbaric index consistently below the threshold for diagnosis; and preeclampsia, defined as gestational hypertension and proteinuria. Results indicate small and nonsignificant differences in 24-hour mean of ambulatory pressures between "detected" and "undetected" gestational hypertension at all stages of pregnancy, in contrast with highly significant differences between these two groups and normotensive pregnancies. Average office blood pressure values were similar for preeclampsia, "detected," and "undetected" gestational hypertension. The hyperbaric index was, however, significantly higher for women with preeclampsia after 20 weeks of gestation as compared with all other groups and higher for women with either "detected" or "undetected" gestational hypertension as compared with normotensive pregnant women. The incidence of preterm delivery and intrauterine growth retardation were similar for "detected" and "undetected" gestational hypertension but significantly lower for normotensive women. In pregnancy, the hyperbaric index derived from ambulatory monitoring is markedly superior to office measurements for diagnosis of what should be truly considered gestational hypertension, as well as for prediction of the outcome of pregnancy.

Evaluation of ambulatory and self-initiated blood pressure monitors by pregnant and postpartum women

OBJECTIVE

To investigate the acceptability of an ambulatory blood pressure (ABP) monitor (SpaceLabs 90207) and a self-initiated blood pressure monitor (Omron HEM-705CP) to pregnant women.

METHODS

Acceptability of the SpaceLabs 90207 and Omron HEM- 705CP monitors was evaluated, using a modified British Hypertension Device assessment form, by () healthy, pregnant women at <15 weeks (n = 120), 35-37 weeks (n = 81), and 5-9 weeks postpartum (n = 86); and () women with preeclampsia (n = 52).

MAIN OUTCOME MEASURES

A monitor was acceptable if a woman graded the overall impression as "good" or "very good."

RESULTS

Healthy women at <15 and 35-37 weeks' gestation and preeclamptic women reported the SpaceLabs 90207 monitor caused discomfort in 54%, 52%, and 60%, interfered with activities in 38%, 40%, and 23%, and disturbed sleep in 62%, 52% and 31%, respectively. Fewer than 12% in any group reported these problems with the Omron HEM-705CP monitor. In the 78 women who evaluated both monitors at 35-37 weeks, the SpaceLabs 90207 and Omron HEM-705CP were acceptable to 78% and 95% of healthy women, respectively (p = 0.005). Women with preeclampsia rated the Space-Labs 90207 as "bad" or "fair" (14%), "good" (58%), and "very good" (28%) compared with "bad" or "fair" (8%), "good" (28%), and "very good" (64%) for the Omron HEM-705CP monitor (p = 0.009).

CONCLUSIONS

Pregnant women found the less intensive blood pressure monitoring with the Omron HEM-705CP more acceptable than the 24-h ABP monitoring with the SpaceLabs 90207. If accurate self-initiated blood pressure devices become available, pregnant women would prefer this method of home blood pressure monitoring.

The relation between maternal work, ambulatory blood pressure, and pregnancy hypertension

STUDY OBJECTIVE

The purpose of the study was to determine the relations between maternal work, ambulatory blood pressure in mid-pregnancy, and subsequent pregnancy outcome.

DESIGN

Data were studied on 933 healthy normotensive primigravidas who had been enrolled into a study on the predictive value of ambulatory blood pressure measurement performed between 18 and 24 weeks gestation. They were classified into three groups depending on whether they were at work (working group, n=245), not working (not working group, n=289), or normally employed but chose not to work (ENK group, n=399), on the day monitoring was performed.

SETTING

The Rotunda Hospital (a large maternity hospital), Dublin, Ireland.

MAIN RESULTS

Adjusted for age, body mass index, smoking, drinking, and marital status, women at work had higher mean daytime systolic (p<0.01) and diastolic (p<0.01) and 24 hour systolic pressures (p=0.03) compared with those not working. The rate of subsequent development of pre-eclampsia was significantly higher (odds ratio 4.1, 95% CI 1.1 to 15.2, p=0.03) among those at work compared with those not working. The association between pre-eclampsia and maternal work remained significant (odds ratio 5.5, 95% CI 1.1 to 27.8, p=0.04) even after allowing for the confounding factors of age, smoking, body mass index, and marital status. When daytime systolic and diastolic blood pressure were added to the regression analysis the risk ratios for pre-eclampsia remained high but did not quite reach statistical significance (odds ratio 4.7, 0.90 to 24.8, p=0.066). Birth weight and placental weight were not predicted by work status or blood pressure.

CONCLUSIONS

A significant independent relation was found between maternal work and ambulatory blood pressure levels in mid-pregnancy. In addition, it was found that maternal work was significantly associated with the subsequent development of pre-eclampsia