The detection, investigation and management of hypertension in pregnancy: full consensus statement

Fall in mean arterial pressure and fetal growth restriction in pregnancy hypertension: an updated metaregression analysis

OBJECTIVE

To update our previous analysis of randomized controlled trials in pregnancy hypertension, which discerned that greater treatment-induced decreases in maternal mean arterial pressure (MAP) appear to adversely affect fetal growth.

METHODS

We conducted an English-language computer search of MEDLINE, Hypertension in Pregnancy, the relevant Cochrane reviews, and the bibliographies of retrieved papers, review articles, and standard obstetric and toxicology texts. Metaregression analysis was used to compare the change in MAP from enrollment to delivery with birth weight.

RESULTS

Seven new trials with 335 women were added to the 27 trials with 2305 women previously reported. No new trials reported on the frequency of small for gestational age infants. Treatment-induced mean difference in MAP was associated with lower mean birth weight (slope: -17.55 [SD 6.67], r2 = 0.19, Spearman's non-parametric p = 0.031, Pearson's parametric p = 0.013). Therefore, over the range of reported mean differences in MAP, a 10 mm Hg fall in MAP was associated with a 176 g decrease in birth weight, and 19% of the birth weight difference between trials could be explained by differential blood pressure control.

CONCLUSION

These results strengthen the association between blood pressure control and restricted fetal growth, and reinforce the need for new data to elucidate optimal antihypertensive use for mild to moderate pregnancy hypertension.

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.

Transforming growth factor-beta 1 does not relate to hypertension in pre-eclampsia

1. Pre-eclampsia is a human disease of pregnancy characterized by high blood pressure, proteinuria and end-organ damage, if severe. Pre-eclampsia is thought to be related to changes in early placental development, with the formation of a shallower than normal placental bed. 2. Transforming growth factor (TGF)-beta1 is a multifunctional fibrogenic growth factor involved in immune regulation that is elevated in some populations with a high risk of hypertensive end-organ disease related to increases in endothelin release. Transforming growth factor-beta1 is also an important factor in placental implantation. Alterations in TGF-beta1 may be related to abnormal placental development in early pregnancy and, thus, are a candidate for the development of hypertension in pre-eclampsia. 3. The aim of the present study was to examine the placental distribution and serum concentration of TGF-beta1 in patients with pre-eclampsia compared with normal pregnancy. 4. Patients with pre-eclampsia (n = 12) were compared with patients with normal pregnancy (n = 14). Transforming growth factor-beta1 was determined by TGF-beta1 Max ELISA (Promega, Madsion, WI, USA) after serum dilution (1/150) and acid activation. Placental distribution was determined by immunostaining with TGF-beta1 (Santa Cruz, Santa Cruz, CA, USA; 20 ng/mL) and the villi and decidual trophoblast were scored for intensity and extent of staining. 5. Patients with pre-eclampsia had a mean gestational age of 36 weeks, whereas those with a normal pregnancy had a mean gestational age of 39.0 +/- 0.4 weeks. There was no difference in TGF-beta1 concentration between the two groups (mean (+/-SEM) 27.1 +/- 1.0 vs 26.4 +/- 0.7 pg/mL for normal pregnancy and pre-eclampsia, respectively; P = 0.73, Mann-Whitney U-test). There was no correlation between systolic or diastolic blood pressure and TGF-beta1 concentration (regression analysis P = 0.4 and 0.2). Immunostaining was absent in the villous trophoblast cells and endovascular and extravillous trophoblast of term placentas. 6. Although TGF-beta1 is present in trophoblast cells in early pregnancy during placental development, TGF-beta1 concentrations were not increased in the placenta at term in pre-eclampsia and there was no correlation between blood pressure and serum TGF-beta1, suggesting that TGF-beta1 does not play a role in the development of late gestation pre-eclampsia and hypertension.

Efficacy and safety of nifedipine tablets for the acute treatment of severe hypertension in pregnancy

OBJECTIVE

The purpose of this study was to determine whether the slower- and longer-acting nifedipine tablets were as effective and safe as the rapid onset and short-acting nifedipine capsules for the treatment of acute severe hypertension in pregnancy.

STUDY DESIGN

Sixty-four women in the second half of pregnancy who were not in labor randomly received 10 mg nifedipine tablets (n = 55 studies) or 10 mg nifedipine capsules (n = 74 studies) if blood pressure was > or =170/110 mm Hg. Blood pressure, heart rate, and cardiotocography were monitored over the subsequent 90 minutes. Successful treatment was a target blood pressure of 110 to 169/80 to 109 mm Hg after 90 minutes; unsuccessful treatment included fetal distress at any stage, the requirement for additional treatment (intravenous hydralazine), or the development of hypotension by 90 minutes after treatment.

RESULTS

Nifedipine capsules lowered blood pressure further (28/19 vs 21/13 mm Hg; P =.03) than nifedipine tablets, but more than three quarters of each group had a successful treatment. Twice as many women (28%) who received nifedipine tablets required a second dose to achieve successful treatment (P =.05), but fewer women had hypotensive episodes (P =.001). Fetal distress was uncommon in both groups (3%-4%), and both groups were delivered an average of 4 days after the study.

CONCLUSION

Nifedipine tablets, although of slower onset, are as effective as nifedipine capsules for the rapid treatment of severe hypertension in pregnancy.

Platelet activation in the hypertensive disorders of pregnancy

OBJECTIVE

The purpose of this study was to determine whether platelet activation occurs only in preeclampsia or also in normal pregnancy.

STUDY DESIGN

Thirty women with preeclampsia, 30 women with gestational hypertension, 20 women with essential hypertension, 30 pregnant women with normotension, and 30 nonpregnant women were recruited at St George Hospital, Sydney, Australia. Platelet activation was determined by flow cytometry on whole blood samples.

RESULTS

Platelet activation was similar in all groups, except the group with preeclampsia. Compared with normal pregnant women, women with preeclampsia had significantly greater CD62 expression (1.35% vs 0.61%; P =.002), CD63 expression (1.73% vs 0.95%; P <.0001) and annexin V binding (1.03% vs 0.66%;P =.03) and significantly fewer circulating platelet microparticles (33 vs 49 x10(9)/L; P =.001). This was unrelated to other parameters that included platelet counts. Women with gestational hypertension in whom preeclampsia developed did not have enhanced platelet activation profiles.

CONCLUSION

Platelet activation is increased in preeclampsia but not in other hypertensive disorders or in normal pregnancy. This may be part of the pathophysiologic factors of preeclampsia complications but is not predictable by the platelet count and is not apparent in all women with preeclampsia.

What's new in defining hypertension and classifying hypertensive disorders in pregnancy

Hypertensive disorders are the most common medical problems encountered by women during pregnancy and remain a major cause of maternal and fetal mortality and morbidity throughout the world. This article provides an update on the definition and classifications of hypertension in pregnancy and discusses the recent consensus statement from the Australasian Society into the Study of Hypertension in Pregnancy (ASSHP). A review of the relevance of the traditional triad of symptoms in the assessment of women for hypertensive disorders in pregnancy is also presented. An understanding of these issues will help midwives accurately assess women and ensure that appropriate management of pregnancies complicated by hypertensive disorders occurs.

A prospective observational study on the accuracy of patient self-testing of urine at an antenatal clinic

This study was performed to assess whether assigning dipstick self-testing of urine to antenatal women maintained accuracy and clinical relevance of the results. A total of 212 women were recruited from the routine antenatal clinic for the assessment of accuracy of self-testing of urine. The women's results were compared to that of the one nurse who routinely performs dipstick testing at the antenatal clinic. Analysis of the results indicates that women tended to over estimate proteinuria.

Body composition and energy metabolism in normotensive and hypertensive pregnancy

OBJECTIVE

To determine whether the insulin resistance syndrome and altered body composition are features of hypertensive pregnancy.

DESIGN

Women were recruited in the third trimester of pregnancy from the antenatal clinic, day assessment unit, and maternity ward of St George Hospital, Sydney.

POPULATION

Women with pre-eclampsia (n = 12), gestational hypertension (n = 12), essential hypertension in pregnancy (n = 11), and normotensive pregnancy (n = 10).

METHODS

Energy metabolism was assessed by indirect calorimetry to measure basal metabolic rate and diet-induced thermogenesis. Body composition was measured as lean body mass, total body water and fat mass by bio-electrical impedance. Blood was collected for measurement of glucose, insulin and lipid profiles. Insulin resistance was indirectly assessed by the insulin and glucose concentrations and diet-induced thermogenesis.

RESULTS

Women with essential hypertension and gestational hypertension were heavier than women with normotensive pregnancies both pre-pregnancy and in the third trimester, whereas women with pre-eclampsia were similar to those with normotensive pregnancy. Women with essential hypertension were otherwise similar to normotensive pregnancy but women with gestational hypertension had a reduced diet-induced thermogenesis and almost double insulin levels. Women with pre-eclampsia had a similar body composition and insulin levels but reduced basal metabolic rate, diet-induced thermogenesis and glucose levels compared with normotensive pregnancy.

CONCLUSIONS

Women who develop gestational hypertension, but not pre-eclampsia, are more likely to be overweight. Women with essential hypertension are similar to women with normotensive pregnancy throughout pregnancy. Both gestational hypertension and pre-eclampsia appear to be associated with some degree of insulin resistance, greater than that occurring in normal pregnancy.

Antihypertensive therapy in pregnancy

Human pregnancy, normally characterized by systemic vasodilation and modest hypotension, can be complicated by underlying maternal hypertension and several unique hypertensive disorders, including pre-eclampsia. Although well-designed and adequately powered clinical trials are critically needed, there have been several recent meta-analyses of this large literature, along with consensus statements and treatment guidelines from three distinct multidisciplinary groups of clinicians and investigators. In this paper we review recent analyses and guidelines, advising on our current approach to antihypertensive therapy in pregnant women.

A genome-wide scan for preeclampsia in the Netherlands

Preeclampsia, hallmarked by de novo hypertension and proteinuria in pregnancy, has a familial tendency. Recently, a large Icelandic genome-wide scan provided evidence for a maternal susceptibility locus for preeclampsia on chromosome 2p13 which was confirmed by a genome scan from Australia and New Zealand (NZ). The current study reports on a genome-wide scan of Dutch affected sib-pair families. In total 67 Dutch affected sib-pair families, comprising at least two siblings with proteinuric preeclampsia, eclampsia or HELLP-syndrome, were typed for 293 polymorphic markers throughout the genome and linkage analysis was performed. The highest allele sharing lod score of 1.99 was seen on chromosome 12q at 109.5 cM. Two peaks overlapped in the same regions between the Dutch and Icelandic genome-wide scan at chromosome 3p and chromosome 15q. No overlap was seen on 2p. Re-analysis in 38 families without HELLP-syndrome (preeclampsia families) and 34 families with at least one sibling with HELLP syndrome (HELLP families), revealed two peaks with suggestive evidence for linkage in the non-HELLP families on chromosome 10q (lod score 2.38, D10S1432, 93.9 cM) and 22q (lod score 2.41, D22S685, 32.4 cM). The peak on 12q appeared to be associated with HELLP syndrome; it increased to a lod score of 2.1 in the HELLP families and almost disappeared in the preeclampsia families. A nominal peak on chromosome 11 in the preeclampsia families showed overlap with the second highest peak in the Australian/NZ study. Results from our Dutch genome-wide scan indicate that HELLP syndrome might have a different genetic background than preeclampsia.

The prevalence and clinical significance of nocturnal hypertension in pregnancy

OBJECTIVE

To determine (a) the prevalence of hypertension during sleep in pre-eclampsia and gestational hypertension, and (b) whether women with hypertension during sleep have worse pregnancy outcomes than hypertensive pregnant women with controlled (normal) blood pressure (BP) during sleep.

DESIGN

Prospective double-blind cohort study.

SETTING

Inpatients and outpatients managed in a day assessment unit (DAU) at St George Hospital, Sydney, Australia.

PARTICIPANTS

A total of 186 hypertensive pregnant women, 158 of whom had successful 24 h BP monitoring; 40% had proteinuric pre-eclampsia (PE), 43% gestational hypertension (GH) and 17% essential hypertension (EH).

INTERVENTIONS

Blood pressure, 24 h non-invasive, monitoring (Spacelabs 90207) was undertaken successfully in 158 women with PE, GH or EH, whether or not they were receiving antihypertensives. Women and clinicians were blinded to results of these BP monitors. Sleep hypertension was defined as BP > 117/68 mmHg at 26-30 weeks or > 123/72 mmHg after 30 weeks gestation.

MAIN OUTCOME MEASURES

Maternal and fetal outcomes were compared between women with and without sleep hypertension and the prevalence of sleep hypertension was determined.

RESULTS

Sleep hypertension was present in 59%, more commonly in PE (79%) than GH/EH (45%), P < 0.0001. Sleep hypertensives also had higher routine sphygmomanometer BPs [137(10)/91(7) mmHg; mean(SD)] than women with normal sleep BP [130(12)/ 87(8) mmHg] P = 0.007, and higher awake ambulatory blood pressure monitoring (ABPM) BPs [137(8)/88(7) versus 127(7)/79(6) mmHg], P < 0.0001. Awake, but not sleep, average heart rate was lower in sleep hypertensives [85(11) versus 91 (10) beats per minute, bpm], P = 0.002. Sleep hypertensives had a significantly greater frequency of renal insufficiency, liver dysfunction, thrombocytopenia and episodes of (awake) severe hypertension (P < 0.05), as well as lower birth weight babies [2715 (808) versus 3224(598) g, P < 0.0001].

CONCLUSIONS

Hypertension during sleep is a common finding in women with hypertensive disorders of pregnancy, particularly pre-eclampsia. These women also have higher awake BPs and a greater frequency of adverse maternal and fetal outcomes. These findings are largely explained by the greater likelihood of pre-eclamptics having sleep hypertension.

Blood-pressure measurement and classification in pregnancy

Pre-eclampsia is usually defined on the basis of new onset hypertension and albuminuria developing after 20 weeks of pregnancy. There are difficulties with measurement of these variables. Conventional sphygmomanometry remains the gold standard for blood-pressure measurement. The value of ambulatory blood-pressure measurement has yet to be established. Oedema is now omitted from all definitions of preeclampsia, although the finding of widespread severe oedema of sudden onset should not be ignored for clinical purposes. Definitions of pre-eclampsia based solely on hypertension and proteinuria ignore the wide clinical variability in this syndrome. Women with no proteinuria but who do have hypertension and other features such as severe headache or other symptoms, thrombocytopenia, hyperuricaemia, disordered liver function, and fetal compromise are likely to have pre-eclampsia. This notion is accepted in the new Australasian definition of pre-eclampsia and more than hinted at in the new American College of Obstetricians and Gynecologists' definition. Definitions used for clinical purposes should be as safe as practical; they are likely to include a considerable number of false positives. Most research studies are weakened if patients without the disease are included. Therefore, a separate stringent research definition of pre-eclampsia we also suggest.