Prediction Of Pregnancy-induced Hypertension Research Articles

Placental volume and three‐dimensional power Doppler analysis in prediction of pre‐eclampsia and small for gestational age between Week 11 and 13 weeks and 6 days of gestation

To assess three-dimensional placental volume measurement and three-dimensional power Doppler (3D-PD) indices between 10 weeks and 6 days and 13 weeks and 6 days in predicting pregnancy-induced hypertension (PIH) and small for gestational age (SGA). Three hundred and eight women undergoing fetal nuchal translucency measurement were prospectively assessed using three-dimensional ultrasound in order to measure placental volume and 3D-PD indices: vascularization index (VI), flow index (FI) and vascularization flow index (VFI), using the VOCAL software. The outcome was scored as normal, PIH, SGA or both. Eight women developed PIH and ten delivered SGA; and 17 developed PIH or SGA. The age, gestational age at the examination or delivery, number of the pregnancy and the nuchal translucency, were similar in all groups. The placental volume, FI and VFI were similar between the groups. The VI was significantly lower when PIH developed (7.86 ± 3.92 vs. 12.02 ± 7.09 in the normal group, P = 0.035). The crown-rump length (CRL) was significantly smaller in the group where either PIH or SGA developed compared to normal outcome (54.29 ± 6.50 and 59.04 ± 8.89, respectively, P = 0.02). Placental volume is not appropriate for early prediction of PIH or SGA, whereas the VI may be of some potential in detection of PIH. The significance of small CRL in these patients should be further tested.

Spectral Analysis of Heart Rate Variability for Early Prediction of Pregnancy-Induced Hypertension

The early prediction of pregnancy-induced hypertension (PIH), a common morbid disorder of pregnancy is unsatisfactory. Therefore, in the present study we have investigated the role of spectral analysis of heart rate variability (HRV) in the early prediction of PIH. Spectral analysis of HRV was performed in three groups of subjects (Group I: normal pregnant women; Group II: pregnant women with risk factors, but did not develop PIH; Group III: pregnant women with risk factors and developed PIH). It was observed that the LF-HF ratio, the most sensitive indicator of sympathovagal balance, was significantly high (p < 0.01) since early pregnancy in group III compared to other groups, which was significantly correlated with heart rate and blood pressure. It was suggested that the predictive knowledge of sympathovagal imbalance should be utilized in designing the prevention and management of PIH.

Comparison between three‐dimensional placental volume at 12 weeks and uterine artery impedance/notching at 22 weeks in screening for pregnancy‐induced hypertension, pre‐eclampsia and fetal growth restriction in a low‐risk population

To compare the value of three-dimensional placental volume at 12 weeks and uterine artery Doppler at 22 weeks for predicting pregnancy-induced hypertension (PIH), pre-eclampsia and fetal growth restriction in a low-risk population. Over a 20-month period we calculated the placental quotient (PQ = placental volume/crown-rump length) at 11-13 weeks' gestation in all women with singleton pregnancies who booked for delivery in our hospital. At 22 weeks, in the same population, we calculated the mean pulsatility index (PI) of both uterine arteries and the presence of an early diastolic notch was noted. Logistic regression models, the PQ and Doppler parameters were used to compare the two screening methods for subgroups of pregnancy outcome. Complete outcome data were obtained in 2489 consecutive singleton pregnancies. Logistic regression models for the detection of pre-eclampsia had a sensitivity of 38.5% (PQ) vs. 44.8% (Doppler); for the detection of small-for-gestational age (SGA) the sensitivity was 27.1% (PQ) vs. 28.1% (Doppler) at a specificity of 90%. Taking a PQ of <or= 10th centile, a mean uterine PI of >or= 90th centile and a bilateral notch, the sensitivity for detection of SGA was 25.0%, 20.2% and 22.0%, respectively; for PIH it was 9.5%, 4.8% and 4.8%; for pre-eclampsia without SGA it was 20.0%, 28%, 12%; for PIH/pre-eclampsia with SGA it was 30.8%, 46.1% and 69.2%. In the group with the most severe complications, in which delivery took place before 34 weeks, the sensitivity was 50.0%, 50.0% and 38.9%, respectively. PQ at 12 weeks and uterine artery Doppler at 22 weeks have similar sensitivities for predicting pre-eclampsia and fetal growth restriction, although uterine artery Doppler is marginally more sensitive for the prediction of pre-eclampsia. While both methods are insufficient for screening in a low-risk population, the PQ method has the potential advantage of being performed in the first trimester.

Predicting pregnancy-induced hypertension with dynamic hemodynamics

Aim: To study dynamic changes in the hemodynamic parameters in pregnant women during different weeks of gestation and to comprehend changes to the cardiovascular system in normal pregnant women and in patients with pregnancy-induced hypertension (PIH), with the object of finding predictors of pregnancy-induced hypertension. Methods: Radialis artery pulse waves of 132 pregnant women were examined from 10 weeks of gestation onward, and the subjects’ hemodynamics were examined every 4 weeks. Results: In the women with PIH hemodynamic changes occurred earlier than the onset of disease and even presented in early pregnancy; there might be another mode, and there were factors disturbing the blood pressure modulating mechanism. Conclusion: The prediction of PIH from the dynamic changes in hemodynamic parameters has significant implications for clinical practice.

Ambulatory blood pressure monitoring, uterine resistances and cardiovascular tests as predictors of pregnancy-induced hypertension

Several blood pressure (BP) and autonomic abnormalities have been associated with pregnancy-induced hypertension (PIH) but no noninvasive method has been identified as able to predict the development of PIH. In the present study we examined prospectively 45 consecutive normotensive pregnant women aged 29.9 + 3.3 years at 27 + 4 gestational week, referred to an institutional tertiary care referral center for known risk factors for developing PIH: pre-eclampsia and/or intrauterine growth retardation in previous pregnancy, or abnormal laboratory tests in present pregnancy (hypocalcemia, hyperuricemia). The following tests were performed: echo-Doppler of uterine arteries to evaluate utero-placental resistance index (URI), ambulatory blood pressure monitoring (ABPM) to measure the systolic and diastolic MESOR (Midline Estimating Statistic of Rhythm) defined as the average value of the rhythmic function fitted to the blood pressure data, cardiovascular tests to evaluate the autonomic nervous function (Valsalva manoeuvre, deep breathing test, lying-to-standing test, cold pressor test, isometric handgrip, and power spectral analysis of heart rate variability). Unpaired t test was used to evaluate differences between normotensive and hypertensive women. The logistic regression model with backward selection was used to estimate the probability of PIH. Eighteen women (40 %) developed gestational hypertension. Compared to normotensives, women who developed PIH showed higher systolic (120 ± 6 vs. 114 ± 8 mm Hg respectively; p<0.05) and diastolic MESOR (75 ± 4 vs. 68 ± 5 mm Hg respectively; p< 0.001). The systolic response to Valsalva manoeuvre was significantly increased in women who developed PIH with respect to normotensives (35 ± 10 vs. 29 ± 9 mm Hg, respectively; p<0.05) indicating a sympathetic activation in women with PIH. Power spectral analysis of heart rate variability did not show any significant difference between normotensive women and women who developed PIH. No difference in URI was found between subjects developing hypertension and normotensive women. Logistic regression analysis showed that all variables correctly predicted 88.9% normotensive women and 83.3% women who developed hypertension. Overall prediction was 86.7%. The most relevant parameter for predicting the development of PIH was diastolic MESOR. Cardiovascular tests improved the prediction of PIH. The study shows that ABPM could have a role in the screening of pregnant women at risk of developing hypertension.

ANGIOTENSIN SENSITIVITY TEST REVISITED

Objective: To determinethe validity of a single angiotensin sensitivity test as predictor of pregnancy-inducedhypertension with special reference to the dietary sodium intake at the timeof testing.Methods: The angiotensin sensitivitytest was successfully performed at 32 weeks' gestation in 104 women.In 90 of these women, the 24-h urinary sodium–creatinine ratio was known.Using an effective pressure dose of 10 ng/kg/min as the cutoff level, testcharacteristics were assessed in both the total population and after subdivisioninto a sodium restricted (n = 23) and anunrestricted diet group (n = 67).Results: The incidence of pregnancy-inducedhypertension was 13.4%. The number of positive angiotensin sensitivity testswas 7.5%. Test characteristics showed poor sensitivity (22.2%) and high specificity(94.8%); positive and negative predictive values were 40.0% and 88.7%, respectively.None of the sodium-restricted women was angiotensin sensitive. Sodium restrictiondid not have a significant influence on sensitivity, specificity, and predictivevalues of the test.Conclusion: The angiotensin sensitivitytest is not an appropriate screening test to predict hypertensive disordersof pregnancy. No significant effect of dietary sodium restriction was found.

Usefulness of ambulatory blood pressure monitoring in pregnant women with type 1 diabetes.

Pregnancy in type 1 diabetes is associated with an increased risk of developing pregnancy-induced hypertension (PIH). Ambulatory blood pressure monitoring (ABPM) has been used to screen for preeclampsia in nondiabetic pregnancy. To date, there are no data regarding ABPM during pregnancy in normotensive type 1 diabetic women. This study sought to establish blood pressure (BP) profiles for pregnant type 1 diabetic women using ABPM and determine whether the BP pattern can define a population at risk for developing PIH. ABPM was carried out for one 24-h period during each trimester--in the first trimester between weeks 7 and 12, in the second trimester between weeks 20 and 24, and in the third trimester between weeks 30 and 34--in 22 normotensive pregnant type 1 diabetic and 10 pregnant nondiabetic women. The incidence of PIH was fourfold greater in type 1 diabetic women than in control subjects. Diabetic women showed higher daily diastolic BP in the third trimester compared with nondiabetic pregnant women. Diabetic women who developed PIH in the third trimester showed significantly higher BP profiles throughout gestation than those who remained normotensive. Receiver operator characteristics curves for nighttime systolic BP showed the best predictive capacity for PIH, with a cutoff > 105 mmHg (85% sensitivity and 92% specificity). Our study confirms the early increase of BP in patients who will develop PIH and suggests that nighttime systolic BP >105 mmHg in the second trimester is a useful predictor of PIH. ABPM may be useful in screening for PIH in pregnant diabetic women.

Prediction of pregnancy-induced hypertension

Prediction of pregnancy-induced hypertension

Roll-over test in primigravidae attending a public primary care service.

To determine the roll-over test (ROT) performance in predicting pregnancy-induced hypertension (PIH) in primigravidae aged 15-29 years in a public primary care service. Prospective cohort study enrolling 369 consecutive and initially normotensive primigravidae. The ROT was applied within 28-32 weeks of pregnancy. PIH was defined as diastolic blood pressure (DBP) 90 mm Hg or systolic blood pressure (SBP) 140 mm Hg, or a rise in DBP 15 mm Hg or a rise in SBP 30 mm Hg. The ROT prognostic properties were calculated, and a receiver operating characteristic (ROC) curve was constructed. For the 20 mm Hg cutoff point, sensitivity was 20% and specificity was 93%. Positive and negative predictive values were, respectively, 23% and 92%, for a PIH cumulative incidence of 9.5%. With other cutoff points, the ROC curve showed a poor discriminatory value of the test. The ROT was not useful for predicting PIH in a primary prenatal care setting.

Color Doppler ultrasound, pregnancy-induced hypertension and small-for-gestational-age fetuses

Objective: The nomogram of blood velocity flow resistance of the spiral arteries was built at 13–25 gestational weeks. Thereafter, by using the nomogram we tried to assess the results of the color Doppler examination of the uteroplacental circulation at the second trimester to predict pregnancy-induced hypertension (PIH) and small-for-gestational-age (SGA). Methods: Two groups of patients were studied. Group 1, for the establishment of the nomogram, included 175 uncomplicated pregnancies with gestational ages ranging from 13–25 weeks. The Doppler flow waveforms of the spiral arteries were measured once for each pregnancy in the studies. Group 2 consisted of 305 singletons selected consecutively for prospective study to confirm the occurrence of PIH or SGA. They were scanned twice for the measurements of the spiral artery waveforms at 13–19 and 20–25 weeks, respectively to test which gestational weeks interval in the nomogram is most sensitive in predicting PIH and SGA. Results: The 5th, 50th and 95th percentiles of the pulsatility index (PI) values of the nomogram at the second trimester were used as the cut-off points to predict pregnancies complicated with SGA or PIH at delivery. Using the receiver operator curve, the 50th percentiles of the PI values of the nomograms were chosen as predictives for the development of PIH and SGA. At 13–19 gestational weeks, the specificities in predicting PIH and SGA were 50.71% and 49.82%, respectively, and the sensitivities were 52.00% and 50.00%, respectively. The calculated Cohen's Kappa statistics were 0.008 and 0.001, respectively in predicting PIH and SGA. At 20–25 gestational weeks, the specificities in predicting PIH and SGA were 49.64% and 49.46%, respectively, and the sensitivities were 56.00% and 57.14%, respectively. The calculated Cohen's Kappa statistics were 0.017 and 0.022, respectively in predicting PIH and SGA. Conclusion: The measurements of uteroplacental blood flow velocity waveforms at the second trimester are not sensitive enough to be an early screening tool for PIH and SGA in the low risk, non-selected pregnancy population. The fact suggests that in most gravidas complicated with PIH and SGA, the physiological process of trophoblastic invasion in the spiral artery was not prevented before the 25th gestational week.

First Trimester Biological Markers for the Prediction of Pregnancy-Induced Hypertension

The purpose of this study is to predict pregnancy-induced hypertension (PIH) by standard methods at the first antenatal visit prior to the 12th gestational week (GW). This is a retrospective study of 1189 primipara and 957 multipara who delivered singleton babies having no major malformations after the 32nd GW. Multiple regression analysis for the development of PIH was performed using the mean arterial blood pressure (MBP), body mass index (BMI), hematocrit count at the first visit prior to the 12th GW, a family history of hypertension number of pregnancies, number of deliveries, past history of hypertension and evidence of threatened abortion as explanatory variables in primipara and multipara, respectively. We obtained a significant regression equation in both primipara and multipara. Multiple correlation coefficient for primipara was 0.40223 (p < 0.01) and for multipara was 0.50764 (p < 0.01). When MBP was over 80 mm Hg, BMI was over 23.6, a family history of hypertension was present, or a past history of hypertension was present, these variables were significantly correlated with the development of PIH both in primipara and multipara. By combining these variables, we obtained 32.7% positive predictive value, 93.5% negative predictive value, 31.7% sensitivity, and 93.7% specificity in primipara and 24.6%, 96.7%, 52.6%, and 89.8% in multipara, respectively. As the incidence of PIH was 8.7% in primipara and 5.9% in multipara, we could predict 3.7 and 4.1 times higher than the true incidence. PIH can therefore be predicted by the simple combination of MBP, BMI, a family history of hypertension, and a past history of hypertension prior to the 12th GW. It can also be predicted by the multiple-regression equation with the use of nine explanatory variables.

Second and Early Third Trimester Atrial Natriuretic Peptide (ANP) Levels in Pregnancies Subsequently Complicated by Hypertension

To explore the clinical utility of measuring atrial natriuretic peptide (ANP) in the second and early third trimesters of pregnancy in order to predict pregnancy induced hypertension (PIH). The study was done in a University Teaching Hospital. A prospective study of 200 women in their first pregnancy was conducted. ANP was measured at 2 gestational windows, 20-26 weeks and 30-34 weeks. This was correlated with pregnancy outcomes, in particular PIH. Student's t-test was used to compare ANP levels between women who developed PIH and those who did not. The receiver operator curve (ROC) was used to determine its clinical utility. ANP levels were lower at 20-26 weeks in women who subsequently developed PIH but there was no significant difference at 30-34 weeks between women who had normotensive pregnancies and those who later developed PIH. The character of the ROC would indicate that it is not useful for prediction. ANP levels in the second and early third trimesters has limited clinical utility for the prediction of PIH.

Prediction of pregnancy-induced hypertension by isometric exercise.

The purpose of this study is to evaluate an isometric exercise (Hand-Grip test) as a method to predict pregnancy-induced hypertension (PIH). One hundred and twenty-five pregnant women were given the Hand-Grip (HG) test before the 15th gestational week. The Hand-Grip test was rated positive when the systolic blood pressure increased 15 mmHg or more during isometric exercise or decreased 14 mmHg or more immediately after isometric exercise. As a result, the Hand-Grip test had the highest sensitivity (81.8%) and specificity (68.4%) for predicting PIH, compared to other risk factors. The positive predictive value was 20% (second highest among risk factors, the actual incidence of hypertension was 8.8%), and the negative predictive value was 97.5% (highest). In conclusion, by use of a very simple Hand-Grip test early in gestation, we are able to predict PIH with the highest sensitivity.

Comparison of cardiovascular reflex tests and blood pressure measurement in prediction of pregnancy-induced hypertension

A changed pressor response to some cardiovascular reflex tests and an increase in midtrimester blood pressure has been reported to precede the appearance of hypertension in pregnancy-induced hypertensive disorders (PIH). In order to compare the value of midtrimester blood pressure with the cardiovascular reflex tests, in predicting the risk of PIH, the Valsalva manoeuvre, the orthostatic test, the deep breathing test and the isometric handgrip test were performed prospectively in 94 women studied once at 21–29 weeks of pregnancy. Eight subjects developed PIH 3–12 weeks after the testing. The resting blood pressure in midpregnancy was related to PIH later in pregnancy. The most powerful measures were the supine diastolic resting blood pressure (odds ratio, 1.24; 95% confidence limits, 1.08–1.43) and the mean arterial pressure (odds ratio, 1.25; 95% confidence limits, 1.09–1.44). Signs of autonomic dysfunction were found in 37% of the patients developing PIH and in 8% of the healthy remaining subjects ( P = 0.04). The results show that the preclinical stage of PIH is associated with some changes in the neural hemodynamic control. However, cardiovascular reflex tests do not add much information on the risk of PIH compared with measuring of the resting blood pressure during mid-pregnancy.

Prediction of pregnancy-induced hypertension by means of the urinary calcium:creatinine ratio.

To investigate the importance of the urinary calcium:creatinine ratio as a prognostic marker for pregnancy-induced hypertension. A prospective study which measured the urinary calcium:creatinine ratio at 20-30 weeks' gestation. Patients' medical records were examined, blind to all urinary assay results, to determine the development of pre-eclampsia or gestational hypertension. A first-morning urine sample was collected from 456 normotensive pregnant women, at 20-30 weeks' gestation, attending a hospital maternity outpatients' clinic for routine antenatal care. The mean urinary calcium:creatinine ratio for women (n = 392) with a normotensive outcome of pregnancy, 0.52 (SD 0.32), was not significantly different from the ratios in those women who developed pre-eclampsia (n = 16), 0.49 (SD 0.32) or gestational hypertension (n = 48), 0.57 (SD 0.41). Significant risk factors for development of gestational hypertension, as estimated by logistic regression, were mean arterial blood pressure greater than 87.6 mmHg, Caucasian race, non-smoking and nulliparity. Within the cohort studied, the calcium:creatinine ratio measured in asymptomatic women at 20-30 weeks' gestation was an unsatisfactory prognostic marker for development of pregnancy-induced hypertension. The major interpopulation, as well as intrapopulation, variation in calcium levels suggests that previous reported findings may not be readily generalised.

Usefulness of the urinary microalbumin/creatinine ratio in predicting pregnancy-induced hypertension

In 199 normotensive pregnant women at 20 and 30 weeks of gestation, a fasting urinary albumin/creatinine ratio (FU Alb/Cr) was evaluated to predict pregnancy-induced hypertension (PIH). FU Alb/Cr in patients destined to develop PIH was significantly high compared to that in normotensive women. When FU Alb/Cr of more than 16 was considered to represent a positive test result, the negative predictive value was 94% and 96%, respectively. FU Alb/Cr is a useful screening tool for PIH.

A longitudinal study of maternal digoxin-like immunoreactive substances in normotensive pregnancy and pregnancy-induced hypertension

The serum of women in the third trimester of pregnancy demonstrates cross-reactivity with some commercially available antibodies to digoxin. A number of studies have suggested that levels of this digoxin-like immunoreactive substance(s) are further increased in patients with pregnancy-induced hypertension, and some have proposed that the digoxin-like immunoreactive substance could be useful as a predicitor of pregnancy-induced hypertension. We measured digoxin-like immunoreactive substance levels every 2 weeks throughout the third trimester in 170 women; of these, 20 developed hypertension. Digoxin-like immunoreactive substance levels rose with gestational age. A graph of the slope of digoxin-like immunoreactive substance plotted against gestational age was fitted for the results obtained from each woman. There was no significant difference in the mean rate of increase of digoxin-like immunoreactive substance level per week between pregnancy-induced hypertension and normotensive pregnancy, nor was there any difference between these two groups at any gestational age studied. These results suggest that measuring digoxin-like immunoreactive substance levels is not useful as a predictor of pregnancy-induced hypertension.

The roll over test is not of value in predicting pregnancy induced hypertension

As a predictor of pregnancy induced hypertension (PIH) the roll over test (ROT) has conflicting predictive values in the literature, possibly as a result of sample size, composition or methodology. In this study the roll over test was performed on 600 African women in their first pregnancy and at 26-32 weeks. The test was positive in 15% of women and had a positive predictive value of only 20%. It is concluded that the roll over test is of no value in the prediction of PIH.

The clinical utility of the roll-over test in predicting pregnancy-induced hypertension in a high-risk Andean population

The utility of the roll-over test (ROT) as a prognostic tool for predicting pregnancy-induced hypertension (PIH) was examined in primiparas in Quito, Ecuador. In Study I, 14 of 16 subjects with a + ROT developed PIH (positive predictive value (PPV) = 88%); only 2 of 27 subjects with a - ROT developed PIH (negative predictive value (NPV) = 92.5%). In Study II ( n = 66), the PPV and NPV were 71.4% and 78.6%, respectively. Data from these and previous studies indicate that although the ROT is not a perfect predictor, its advantages recommend usage in populations with high PIH-associated maternal and perinatal mortality.

Change in plasma cystyl aminopeptidase (oxytocinase) between 30-34 weeks' gestation as a predictor of pregnancy-induced hypertension.

Ninety-two primigravidas were screened biweekly by measurement of plasma cystyl aminopeptidase from 28 weeks' gestation until delivery. Fourteen developed hypertension with or without proteinuria after 36 weeks. The hypertensive group had significantly higher levels of the enzyme at 30 weeks, although this difference was not significant at 34 weeks. The rise in the hypertensive group was less than 50% between weeks 30-34 in all cases, whereas it was over 50% in all but two of the 43 controls. The difference in the rates of increase of the enzyme and its action on antidiuretic hormone may have some bearing on the subsequent development of hypertension.