The detection, investigation and management of hypertension in pregnancy: executive summary

Hypertension in pregnancy

Hypertension complicates 5% to 7% of all pregnancies. A subset of preeclampsia, characterized by new-onset hypertension, proteinuria, and multisystem involvement, is responsible for substantial maternal and fetal morbidity and is a marker for future cardiac and metabolic disease. This American Society of Hypertension (ASH) position paper summarizes the clinical spectrum of hypertension in pregnancy, focusing on preeclampsia. Recent research breakthroughs relating to etiology are briefly reviewed. Topics include classification of the different forms of hypertension during pregnancy, and status of the tests available to predict preeclampsia, and strategies to prevent preeclampsia and to manage this serious disease. The use of antihypertensive drugs in pregnancy, and the prevention and treatment of the convulsive phase of preeclampsia, eclampsia, with intravenous MgSO(4) is also highlighted. Of special note, this guideline article, specifically requested, reviewed, and accepted by ASH, includes solicited review advice from the American College of Obstetricians and Gynecologists.

Calcium channel blockers prevent endothelial cell activation in response to necrotic trophoblast debris: possible relevance to pre-eclampsia

AIMS

Pre-eclampsia is characterized by endothelial activation, which is triggered by placental factor(s). One such factor may be trophoblastic debris that is shed into the maternal blood to become trapped against the maternal pulmonary endothelium. Phagocytosis of necrotic trophoblastic debris (NTD) induces endothelial cell activation with increased secretion of interleukin-6 (IL-6) and transforming growth factor β1 (TGFβ1), which may induce systemic endothelial cell activation. In addition to its effects on vascular smooth muscle, evidence suggests that nifedipine may also affect the endothelium, contributing to the therapeutic benefits of the drug. We investigated whether nifedipine could reverse the endothelial cell activation induced by NTD.

METHODS AND RESULTS

Trophoblastic debris was collected from placental explants and exposed to endothelial cells with or without nifedipine, verapamil, or a nitric oxide (NO) donor for 24 h. Endothelial cell activation was measured by cell-surface intracellular adhesion molecule-1 and E-selectin, as well as monocyte adhesion. The activation of endothelial cells exposed to NTD or sera from pre-eclamptic women was significantly reduced by nifedipine or verapamil. In addition, the increases in the levels of IL-6 or TGFβ1 in conditioned media from endothelial cells following phagocytosis of NTD were significantly reduced by nifedipine. These actions of nifedipine were reversed by the NO synthetase inhibitor l-NAME and mimicked by a NO donor.

CONCLUSION

Our results suggest that calcium channel blockers may have a direct effect upon endothelial cells, reducing the endothelial cell activation that is a key pathogenic feature of pre-eclampsia. This action may be mediated, in part, by NO.

Association between World Health Organization categories of body mass index and relative risks for weight-related pregnancy outcomes: a retrospective cohort study

OBJECTIVE

To analyse the dose-dependent effect of body mass index (BMI) categories for common pregnancy outcomes.

METHODS

A retrospective cohort study of all deliveries that occurred between 1 January 2005 and 31 December 2009 in a tertiary maternity centre, in Sydney Australia. Common pregnancy outcomes were analysed against World Health Organization (WHO) BMI categories using multiple logistic regression analysis.

RESULTS

From a total of 18,304 pregnancies, 9087 singleton pregnancies with complete data-sets were identified. Of these pregnancies, 4000 (44%) had a normal BMI, 470 (5.2%) were underweight, 2293 (25.2%) were overweight, 1316 (14.5%) were obese class I, 630 (6.9%) were obese class II and 378 (4.2%) were obese class III. Using the normal BMI category as the reference, there was a clear dose effect of BMI categories for hypertension (P < 0.001), pre-eclampsia (P < 0.001), caesarean section (P < 0.001), macrosomia (P < 0.001), large for gestational age (P < 0.001), small for gestational age (P < 0.001) and neonatal respiratory distress (P = 0.039). In contrast, despite a significant association with BMI (P < 0.001), a dose-dependent effect was not found for gestational diabetes.

CONCLUSION

The results of our study have important clinical significance as the data, using WHO BMI categories, more accurately help stratify risk assessment in a clinically relevant dose-dependent relationship.

Cardiovascular drugs in pregnancy

Cardiovascular drugs are used in pregnancy to treat maternal and fetal conditions. Mothers may also require drug therapy postpartum. Most cardiovascular drugs taken by pregnant women can cross the placenta and therefore expose the developing embryo and fetus to their pharmacologic and teratogenic effects. These effects are influenced by the intrinsic pharmacokinetic properties of a given drug and by the complex physiologic changes occurring during pregnancy. Many drugs are also transferred into human milk with potential adverse effects on the nursing infant. This article summarizes some of the literature concerning the risks and benefits of using cardiovascular drugs during pregnancy.

Nifedipine versus labetalol in the treatment of hypertensive disorders of pregnancy

PURPOSE

To assess the maternal and fetal outcomes of pregnancies affected by hypertensive disorders treated with nifedipine versus labetalol.

METHODS

A retrospective study in hypertensive patients treated during pregnancy with nifedipine or labetalol was conducted. After the charts review the patients were divided in the four groups: gestational hypertension (113 patients); mild preeclampsia (77 patients); severe preeclampsia (31 patients); HELLP syndrome (21 patients). The pregnancy and neonatal records were analyzed by paired and unpaired t test.

RESULTS

We found that there was an higher rate of intrauterine growth restriction infants among women treated with labetalol compared with those treated with nifedipine (38.8 vs. 15.5 %; p < 0.05), but only in the subgroup of women affected by Gestational Hypertension and Mild Preeclampsia. In this group was also higher the rate of fetal worsening assessed by fetal heart rate tracing (33.3 vs. 14.2 %; p < 0.05). No neonatal malformations and no differences in the rate of adverse side effects were observed.

CONCLUSIONS

Antihypertensive therapy in pregnancy with Labetalol may have the potential to impair fetal behavior in low degrees hypertensive diseases of pregnancy. Optimal care must balance the potentially conflicting risks and benefits to mother and fetus.

Genome-wide association scan identifies a risk locus for preeclampsia on 2q14, near the inhibin, beta B gene

Elucidating the genetic architecture of preeclampsia is a major goal in obstetric medicine. We have performed a genome-wide association study (GWAS) for preeclampsia in unrelated Australian individuals of Caucasian ancestry using the Illumina OmniExpress-12 BeadChip to successfully genotype 648,175 SNPs in 538 preeclampsia cases and 540 normal pregnancy controls. Two SNP associations (rs7579169, p = 3.58×10⁻⁷, OR = 1.57; rs12711941, p = 4.26×10⁻⁷, OR = 1.56) satisfied our genome-wide significance threshold (modified Bonferroni p<5.11×10⁻⁷). These SNPs reside in an intergenic region less than 15 kb downstream from the 3′ terminus of the Inhibin, beta B (INHBB) gene on 2q14.2. They are in linkage disequilibrium (LD) with each other (r² = 0.92), but not (r²<0.80) with any other genotyped SNP ±250 kb. DNA re-sequencing in and around the INHBB structural gene identified an additional 25 variants. Of the 21 variants that we successfully genotyped back in the case-control cohort the most significant association observed was for a third intergenic SNP (rs7576192, p = 1.48×10⁻⁷, OR = 1.59) in strong LD with the two significant GWAS SNPs (r²>0.92). We attempted to provide evidence of a putative regulatory role for these SNPs using bioinformatic analyses and found that they all reside within regions of low sequence conservation and/or low complexity, suggesting functional importance is low. We also explored the mRNA expression in decidua of genes ±500 kb of INHBB and found a nominally significant correlation between a transcript encoded by the EPB41L5 gene, ∼250 kb centromeric to INHBB, and preeclampsia (p = 0.03). We were unable to replicate the associations shown by the significant GWAS SNPs in case-control cohorts from Norway and Finland, leading us to conclude that it is more likely that these SNPs are in LD with as yet unidentified causal variant(s).

A prospective cohort study investigating associations between hyperemesis gravidarum and cognitive, behavioural and emotional well-being in pregnancy

Objectives

To investigate the association between hyperemesis gravidarum and altered cognitive, behavioural and emotional well-being in pregnancy.

Methods

The study cohort consisted of 3423 nulliparous women recruited in the Screening for Pregnancy Endpoints (SCOPE) study performed in Auckland, New Zealand; Adelaide, Australia; Cork, Ireland; Manchester and London, United Kingdom between November 2004 and August 2008. Women were interviewed at 15±1 weeks' gestation and at 20±1weeks' gestation. Women with a diagnosis of hyperemesis gravidarum (HG) were compared with women who did not have a diagnosis of HG. Main outcome measures included the Short form State- Trait Anxiety Inventory (STAI) score (range 6–24), Perceived Stress Scale score (PSS, range 0–30), Edinburgh Postnatal Depression Scale (EPDS) score (range 0–30 or categories a–c) and behavioural responses to pregnancy score (limiting/resting [range 0–20] and all-or-nothing [range 0–28]).

Results

During the study period 164 women suffered from HG prior to their 15 week interview. Women with HG had significantly higher mean STAI, PSS, EPDS and limiting response to pregnancy scores compared to women without HG. These differences were observed at both 15±1 and 20±1 weeks' of gestation. The magnitude of these differences was greater in women with severe HG compared to all women with HG. Women with severe HG had an increased risk of having a spontaneous preterm birth compared with women without HG (adjusted OR 2.6 [95% C.I. 1.2, 5.7]).

Conclusion

This is the first large prospective study on women with HG. Women with HG, particularly severe HG, are at increased risk of cognitive, behavioural and emotional dysfunction in pregnancy. Women with severe HG had a higher rate of spontaneous preterm birth compared to women without HG. Further research is required to determine whether the provision of emotional support for women with HG is beneficial.

How to manage hypertension in pregnancy effectively

The hypertensive disorders of pregnancy (HDP) are a leading cause of maternal mortality and morbidity in both well and under-resourced settings. Maternal, fetal, and neonatal complications of the HDP are concentrated among, but not limited to, women with pre-eclampsia. Pre-eclampsia is a systemic disorder of endothelial cell dysfunction and as such, blood pressure (BP) treatment is but one aspect of its management. The most appropriate BP threshold and goal of antihypertensive treatment are controversial. Variation between international guidelines has more to do with differences in opinion rather than differences in published data. For women with severe hypertension [defined as a sustained systolic BP (sBP) of ≥160 mmHg and/or a diastolic BP (dBP) of ≥110 mmHg], there is consensus that antihypertensive therapy should be given to lower the maternal risk of central nervous system complications. The bulk of the evidence relates to parenteral hydralazine and labetalol, or to oral calcium channel blockers such as nifedipine capsules. There is, however, no consensus regarding management of non-severe hypertension (defined as a sBP of 140-159 mmHg or a dBP of 90-109 mmHg), because the relevant randomized trials have been underpowered to define the maternal and perinatal benefits and risks. Although antihypertensive therapy may decrease the occurrence of BP values of 160-170/100-110 mmHg, therapy may also impair fetal growth. The potential benefits and risks do not seem to be associated with any particular drug or drug class. Oral labetalol and methyldopa are used most commonly, but many different β-adrenoceptor blockers and calcium channel blockers have been studied in clinical trials.

Association between mannose-binding lectin gene polymorphisms and pre-eclampsia in Brazilian women

PROBLEM

Mannose-binding lectin (MBL) is involved in the maintenance of an inflammatory environment in uterus. High MBL levels have been associated with successful pregnancies whereas low levels are involved in pre-eclampsia (PE) development. Here, we evaluated MBL2 gene polymorphisms in the structural and promoter regions addressing their association with PE.

METHOD OF STUDY

DNA samples from 162 control pregnant women and 157 pregnant PE women were genotyped and data compared with demographic and clinical characteristics.

RESULTS

High frequency of C and D alleles (related to low MBL levels) was observed in PE women when compared to controls (C: 0.08 versus 0.03, P = 0.006; D: 0.10 versus 0.05, P = 0.009). Grouping the MBL genotypes according to phenotype, a higher frequency of OO genotype was observed in PE women when compared to control women (0.15 versus 0.04, P = 0.007).

CONCLUSION

Our data suggest that women with genotypes associated with low MBL levels could be potential PE developers.

ICU nurses' experiences and perspectives of caring for obstetric patients in intensive care: a qualitative study

AIMS AND OBJECTIVES

The aim of this study was to gain an understanding of the experiences and perspectives of intensive care nurses caring for critically ill obstetric patients.

BACKGROUND

Current literature suggests critically ill obstetric patients need specialised, technically appropriate care to meet their specific needs with which many intensive care nurses are unfamiliar. Furthermore, there is little research and evidence to guide the care of this distinct patient group.

DESIGN

This study used a descriptive qualitative design.

METHODS

Two focus groups were used to collect data from 10 Australian intensive care units nurses in May 2007. Open-ended questions were used to guide the discussion. Latent content analysis was used to analyse the data set. Each interview lasted no longer than 60 minutes and was recorded using audio tape. The full interviews were transcribed prior to in-depth analysis to identify major themes.

RESULTS

The themes identified from the focus group interviews were competence with knowledge and skills for managing obstetric patients in the intensive care unit, confidence in caring for obstetric patients admitted to the intensive care unit and acceptance of an expanded scope of practice perceived to include fundamental midwifery knowledge and skills.

CONCLUSION

The expressed lack of confidence and competence in meeting the obstetric and support needs of critically ill obstetric women indicates a clear need for greater assistance and education of intensive care nurses. This in turn may encourage critical care nurses to accept an expanded role of clinical practice in caring for critically ill obstetric patients.

RELEVANCE TO CLINICAL PRACTICE

Recognition of the issues for nurses in successfully caring for obstetric patients admitted to an adult intensive care setting provides direction for designing education packages, ensuring specific carepaths and guidelines are in place and that support from a multidisciplinary team is available including midwifery staff.

Genetic and molecular functional characterization of variants within TNFSF13B, a positional candidate preeclampsia susceptibility gene on 13q

BACKGROUND

Preeclampsia is a serious pregnancy complication, demonstrating a complex pattern of inheritance. The elucidation of genetic liability to preeclampsia remains a major challenge in obstetric medicine. We have adopted a positional cloning approach to identify maternal genetic components, with linkages previously demonstrated to chromosomes 2q, 5q and 13q in an Australian/New Zealand familial cohort. The current study aimed to identify potential functional and structural variants in the positional candidate gene TNFSF13B under the 13q linkage peak and assess their association status with maternal preeclampsia genetic susceptibility.

METHODOLOGY/PRINCIPAL FINDINGS

The proximal promoter and coding regions of the positional candidate gene TNFSF13B residing within the 13q linkage region was sequenced using 48 proband or founder individuals from Australian/New Zealand families. Ten sequence variants (nine SNPs and one single base insertion) were identified and seven SNPs were successfully genotyped in the total Australian/New Zealand family cohort (74 families/480 individuals). Borderline association to preeclampsia (p = 0.0153) was observed for three rare SNPs (rs16972194, rs16972197 and rs56124946) in strong linkage disequilibrium with each other. Functional evaluation by electrophoretic mobility shift assays showed differential nuclear factor binding to the minor allele of the rs16972194 SNP, residing upstream of the translation start site, making this a putative functional variant. The observed genetic associations were not replicated in a Norwegian case/control cohort (The Nord-Trøndelag Health Study (HUNT2), 851 preeclamptic and 1,440 non-preeclamptic women).

CONCLUSION/SIGNIFICANCE

TNFSF13B has previously been suggested to contribute to the normal immunological adaption crucial for a successful pregnancy. Our observations support TNFSF13B as a potential novel preeclampsia susceptibility gene. We discuss a possible role for TNFSF13B in preeclampsia pathogenesis, and propose the rs16972194 variant as a candidate for further functional evaluation.

Does the anti-hypertensive drug clonidine affect the short-term variation in CTG recordings?

BACKGROUND

Cardiotocographic (CTG) recordings of the fetal heart remain standard obstetric practice among hypertensive women. Changes in the short-term variation (STV) in the fetal heart are often attributed to the effect of anti-hypertensive medications, regardless of the fact that this principle has never been validated.

AIM

To assess the STV of CTG recordings pre- and post- the anti-hypertensive medication, clonidine.

METHODS

Forty hypertensive pregnant women, already receiving the anti-hypertensive clonidine, were recruited. The CTGs were conducted pre- and post-dose administration. The CTGs were assessed by the Sonicaid Team® automated CTG analysis (Oxford Instruments, UK) to avoid CTG assessor bias. Baseline fetal heart rate (FHR) (delta change from pre- and post-dose) and STV were compared using spss v.14® utilising Student t-tests.

RESULTS

No statistical difference was found in the pre- and post-baseline FHRs (P = 0.48). The mean delta baseline heart rate before and after drug administration was -0.54 bpm. The STV of the CTGs recorded pre- and post-clonidine dose was also not affected by administration of the drug (P = 0.34). The mean delta STV before and after drug administration was 0.39 ms. Two women received betamethasone 12 mg intramuscularly within the 12-h period prior to CTG recordings to enhance fetal lung maturity. The mean STV for the fetuses of these women pre-drug was 4.8 ms and 13.2 ms post-administration. This was the largest delta seen in all STVs recorded in this dataset.

CONCLUSION

The anti-hypertensive drug clonidine does not alter baseline FHRs or affect the STV of the FHR in hypertensive pregnant women.

Hypertension in pregnancy

Hypertension complicates 5% to 7% of all pregnancies. A subset of preeclampsia, characterized by new-onset hypertension, proteinuria, and multisystem involvement, is responsible for substantial maternal and fetal morbidity and is a marker for future cardiac and metabolic disease. This American Society of Hypertension (ASH) position paper summarizes the clinical spectrum of hypertension in pregnancy, focusing on preeclampsia. Recent research breakthroughs relating to etiology are briefly reviewed. Topics include classification of the different forms of hypertension during pregnancy, and status of the tests available to predict preeclampsia, and strategies to prevent preeclampsia and to manage this serious disease. The use of antihypertensive drugs in pregnancy, and the prevention and treatment of the convulsive phase of preeclampsia, eclampsia, with intravenous MgSO(4) is also highlighted. Of special note, this guideline article, specifically requested, reviewed, and accepted by ASH, includes solicited review advice from the American College of Obstetricians and Gynecologists.

Role of proteinuria in defining pre-eclampsia: clinical outcomes for women and babies

1. The presence of proteinuria is not essential to the diagnosis of pre-eclampsia under many diagnostic consensus statements. The aim of the present study was to assess maternal and perinatal outcomes after proteinuric pre-eclampsia compared with other non-proteinuric disease presentations. 2. An individual patient data review (n = 670) was undertaken for 2003-2006 at a tertiary referral centre in Sydney (NSW, Australia). Women were diagnosed in accordance with the Australasian Society for the Study of Hypertension in Pregnancy Consensus Statement. Data were analysed with the Chi-squared test, t-tests and non-parametric tests. Statistical significance was set at P < 0.05. 3. The proteinuric cohort had higher systolic and diastolic blood pressure recordings than the non-proteinuric cohort (160/102 and 149/94 mmHg, respectively; P < 0.001), and were also administered magnesium sulphate more frequently (44 vs 22%, respectively; P < 0.001), delivered at earlier gestation (37 vs 38 weeks, respectively; P < 0.001), required operative delivery more frequently (63 vs 48%, respectively; P < 0.001) and received more antihypertensive medications during the antenatal period (72 vs 57%, respectively; P < 0.001). Acute renal failure and acute pulmonary oedema were rare. Four cases of eclampsia all occurred in non-proteinuric women. The perinatal mortality rate was lower for the offspring of women with proteinuric pre-eclampsia compared with offspring of non-proteinuric women (13/1000 and 31/1000, respectively; P = 0.006). 4. The results of the present study indicate that the presence of proteinuria denotes a group of women who have higher antenatal blood pressure, who deliver at earlier gestation and require operative delivery more commonly, although it is not an indicator of other markers of maternal morbidity or perinatal mortality.

The ERAP2 gene is associated with preeclampsia in Australian and Norwegian populations

Preeclampsia is a heritable pregnancy disorder that presents new onset hypertension and proteinuria. We have previously reported genetic linkage to preeclampsia on chromosomes 2q, 5q and 13q in an Australian/New Zealand (Aust/NZ) familial cohort. This current study centered on identifying the susceptibility gene(s) at the 5q locus. We first prioritized candidate genes using a bioinformatic tool designed for this purpose. We then selected a panel of known SNPs within ten prioritized genes and genotyped them in an extended set of the Aust/NZ families and in a very large, independent Norwegian case/control cohort (1,139 cases, 2,269 controls). In the Aust/NZ cohort we identified evidence of a genetic association for the endoplasmic reticulum aminopeptidase 1 (ERAP1) gene (rs3734016, P (uncorr) = 0.009) and for the endoplasmic reticulum aminopeptidase 2 (ERAP2) gene (rs2549782, P (uncorr) = 0.004). In the Norwegian cohort we identified evidence of a genetic association for ERAP1 (rs34750, P (uncorr) = 0.011) and for ERAP2 (rs17408150, P (uncorr) = 0.009). The ERAP2 SNPs in both cohorts remained statistically significant (rs2549782, P (corr) = 0.018; rs17408150, P (corr) = 0.039) after corrections at an experiment-wide level. The ERAP1 and ERAP2 genes encode enzymes that are reported to play a role in blood pressure regulation and essential hypertension in addition to innate immune and inflammatory responses. Perturbations within vascular, immunological and inflammatory pathways constitute important physiological mechanisms in preeclampsia pathogenesis. We herein report a novel preeclampsia risk locus, ERAP2, in a region of known genetic linkage to this pregnancy-specific disorder.

ASH position paper: hypertension in pregnancy

The American Society of Hypertension is publishing a series of Position Papers in their official journals throughout the 2008-2009 years. The following Position Paper originally appeared: JASH. 2008;2(6):484-494. Hypertension complicates 5% to 7% of all pregnancies. A subset of preeclampsia, characterized by new-onset hypertension, proteinuria, and multisystem involvement, is responsible for substantial maternal and fetal morbidity and is a marker for future cardiac and metabolic disease. This American Society of Hypertension, Inc (ASH) position paper summarizes the clinical spectrum of hypertension in pregnancy, focusing on preeclampsia. Recent research breakthroughs relating to etiology are briefly reviewed. Topics include classification of the different forms of hypertension during pregnancy, status of the tests available to predict preeclampsia, and strategies to prevent preeclampsia and to manage this serious disease. The use of antihypertensive drugs in pregnancy, and the prevention and treatment of the convulsive phase of preeclampsia, eclampsia, with intravenous magnesium sulfate is also highlighted. Of special note, this guideline article, specifically requested, reviewed, and accepted by ASH, includes solicited review advice from the American College of Obstetricians and Gynecologists.

A Prospective Study of the Impact of Automated Dipstick Urinalysis on the Diagnosis of Preeclampsia

OBJECTIVE

To determine prospectively in hypertensive pregnant women 1) the accuracy of dipstick testing for proteinuria using automated urinalysis, 2) factors that might affect such accuracy, and 3) the potential impact of automated dipstick testing on the accuracy of diagnosis of preeclampsia according to acceptance of proteinuria at either 1 + or 2 + level.

DESIGN

Prospective study.

SETTING

Antenatal day assessment unit and antenatal ward of St George Hospital, a teaching hospital in Sydney, Australia.

POPULATION

170 hypertensive pregnant women attending as outpatients or inpatients.

METHODS

503 midstream urine samples were collected prospectively on separate occasions from 170 women. Full urinalysis was recorded using the Bayer Clinitek 50 automated urinalysis device and Multistix 10SG urinalysis strips (Bayer Diagnostics, Victoria, Australia). Each MSU was analysed for spot protein/creatinine ratio and also for culture and sensitivity if symptoms of a urinary tract infection were present or dipstick included positive nitrites. Urinalysis protein results were compared with spot urinary protein/creatinine ratio (previously shown to correlate with 24-hr urine protein excretion) to determine the accuracy of urinalysis. True proteinuria was defined as a ratio >/= 30 mg protein/mmol creatinine.

RESULTS

False positive dipstick tests ranged from 7% at 3 + level to 71% at 1 + proteinuria level while false negative rates were 7% for "nil" and 14% for "trace" proteinuria, 9% overall. Accepting the dipstick proteinuria result at face value led to an incorrect diagnosis of preeclampsia or gestational hypertension in 85 (50%) women. Dipstick proteinuria was significantly more likely to be correct (true positive/true negative) if diastolic blood pressure was elevated > 90 mmHg (p = 0.032) and in the absence of ketonuria (p = 0.001). Accepting a diagnosis of preeclampsia on the basis of de novo hypertension and dipstick testing alone was accurate less often (70%) when > 1 + was used as a discriminant value than at the 82% of presentations when > 2 + was used (p = 0.001).

CONCLUSION

Accepting "nil" or "trace" proteinuria as a true negative dipstick results fails to identify approximately 1 in 11 hypertensive pregnant women with true proteinuria, a false negative rate that may be acceptable provided these women are subject to ongoing vigilant clinical review. Even with automated urinalysis the false positive rate for dipstick levels >/= 1 + is very high, particularly in the presence of ketonuria and relying on this alone to diagnose preeclampsia leads to significant errors in diagnosis. Accepting >/= 2 + dipstick proteinuria improves overall diagnostic accuracy for preeclampsia at the expense of a higher false negative rate. This study emphasizes the need to confirm dipstick proteinuria with a further test such as a spot urine protein/creatinine ratio in all hypertensive pregnant women, particularly in research studies.

A Survey of Canadian Practitioners Regarding Diagnosis and Evaluation of the Hypertensive Disorders of Pregnancy

BACKGROUND

How Canadian practitioners are diagnosing and managing the hypertensive disorders of pregnancy (HDP), particularly in relation to the 1997 recommendations published by the Canadian Hypertension Society (CHS), is not known.

METHODS

A survey, with French and English versions (and covering diagnosis, evaluation, and management of pregnancy hypertension), was mailed to all members of the Society of Obstetricians and Gynaecologists of Canada (SOGC) (N = 1757, including obstetricians, family doctors practicing obstetrics, and midwives). Additionally, internists [i.e., all nephrologists (N = 191) and a random sample of 25% of general internists (N = 450)] registered with the Royal College of Physicians and Surgeons of Canada were sampled. The survey was distributed in two mailings and one reminder card. Data were entered into Microsoft Access, and Graph Pad Prism used to summarize responses [N (%)]. Differences in practice between specialties were examined, with a Bonferonni correction used to calculate a significant p value based on the number of comparisons and alpha of 0.05.

RESULTS

Respondents numbered 1187 (49.5%), with 466 not informative for the purpose of the study (due to retirement, or practices that do not include pregnant women with hypertension). The final analysis included 721 completed surveys. Most (609, 84.5% of) respondents take blood pressure (BP) with women in the sitting position, and use a mercury sphygmomanometer (79%) and the 5th Korotkoff (61%) sound to designate diastolic BP (dBP). To monitor pregnancies complicated by preeclampsia, most clinicians use the proposed laboratory tests of maternal well-being (usually at least once/week), fetal well-being [nonstress test (NST, at least once/week), and ultrasonographic studies (once weekly to every two weeks)]. There is general agreement that women with preeclampsia should be delivered for uncontrolled hypertension, end-organ dysfunction, or fetal compromise (nonreassuring NST, severe oligohydramnios, biophysical profile < 4, estimated fetal weight < 5th centile, and reversed end-diastolic flow by umbilical artery Doppler velocimetry). Less consensus was seen for delivery for preeclampsia at > 34 weeks, mild asymptomatic HELLP syndrome, hyperreflexia, and absent end-diastolic flow by umbilical artery Doppler velocimetry.

INTERPRETATION

This survey has clarified the current state of practice with respect to the diagnosis and evaluation of women with all types of HDP. In particular, we have identified areas of potential variability in BP measurement, and provided data on the feasibility of enrolling women with sub types of preeclampsia into intervention studies aimed at prolonging pregnancy.

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.

Time Poor: Rushing Decreases the Accuracy and Reliability of Blood Pressure Measurement Technique in Pregnancy

BACKGROUND

In pregnancy, absolute blood pressure (BP) limits define preeclampsia. Therefore, BP in pregnancy should be measured accurately and in accordance with accepted guidelines. Accuracy of BP readings determined by rate of cuff deflation was analyzed. This study also investigated the compliance of clinical staff at Royal Prince Alfred Hospital, Australia, to guidelines for BP measurement.

METHODS

The study was an observational trial of 98 normotensive antenatal or recently postnatal patients. Two BP readings were taken, each with fast (>5 mm Hg/sec) and slow (<or=2 mm Hg/sec) descent of mercury and compared by Bland-Altman analysis. Also, BP techniques used by junior doctors, specialist obstetricians, and midwives were compared using a 9-point scale.

FINDINGS

Australian national guidelines recommend slow descent of mercury. Fast descent underestimated the systolic BP by 9 mm Hg (95% confidence interval [CI], -23 to +5 mm Hg) (p < 0.001). Fast descent measured the diastolic BP within 2 mm Hg (95% CI, -10 to +14 mm Hg) (not different, p = 0.151). Accuracy of fast cuff deflation was 28% for systolic BP and 50% for diastolic BP for <5 mm Hg, and respectively, 64% and 68% for <10 mm Hg, 84% and 80% for <15 mm Hg and 91% and 87% for <20 mm Hg. Compliance with guidelines was greatest for specialists and midwives (p = 0.001) and their most commonly missed feature (76% to 100%) was slow cuff deflation.

INTERPRETATION

Rapid cuff deflation underestimates the systolic BP compared to accepted guidelines (<or=2 mm Hg/sec). Medical and midwifery staff may not follow accepted guidelines for BP measurement, particularly with regard to rate of cuff deflation. Potential misdiagnosis and under-treatment of patients with hypertension may compromise pregnancy outcomes.

The management of severe hypertension

Although definitions of severe hypertension vary, thresholds of >or=160-170 mm Hg systolic and/or >or=110 mm Hg diastolic are in most common usage. A recent focus has been placed on systolic hypertension given the increased pulse pressure in these women. In pregnancy, there is a general consensus that severe hypertension should be treated. Among woman with pre-eclampsia, attention must be paid to other end organ dysfunction, as blood pressure (BP) management is but one aspect of care. The urgency of antihypertensive therapy will depend primarily on the absolute level of BP. However, most clinicians will also consider both the rate of BP rise and the presence of maternal symptoms. Most commonly, severe hypertension is treated with parenteral labetalol or hydralazine, or oral nifedipine (capsules or PA tablet). Other options will depend on local availability. MgSO(4) should not be relied on as an antihypertensive.

A current landscape of provincial perinatal data collection in Canada

BACKGROUND

The Canadian Perinatal Network (CPN) was launched in 2005 as a national perinatal database project designed to identify best practices in maternity care. The inaugural project of CPN is focused on interventions that optimize maternal and perinatal outcomes in women with threatened preterm birth at 22+0 to 28+6 weeks' gestation.

OBJECTIVE

To examine existing data collection by perinatal health programs (PHPs) to inform decisions about shared data collection and CPN database construction.

METHODS

We reviewed the database manuals and websites of all Canadian PHPs and compiled a list of data fields and their definitions. We compared these fields and definitions with those of CPN and the Canadian Minimal Dataset, proposed as a common dataset by the Canadian Perinatal Programs Coalition of Canadian PHPs.

RESULTS

PHPs collect information on 2/3 of deliveries in Canada. PHPs consistently collect information on maternal demographics (including both maternal and neonatal personal identifiers), past obstetrical history, maternal lifestyle, aspects of labour and delivery, and basic neonatal outcomes. However, most PHPs collect insufficient data to enable identification of obstetric (and neonatal) practices associated with improved maternal and perinatal outcomes. In addition, there is between-PHP variability in defining many data fields.

CONCLUSION

Construction of a separate CPN database was needed although harmonization of data field definitions with those of the proposed Canadian Minimal Dataset was done to plan for future shared data collection. This convergence should be the goal of researchers and clinicians alike as we construct a common language for electronic health records.

ASH position paper: hypertension in pregnancy

The American Society of Hypertension is publishing a series of Position Papers in their official journals throughout the 2008-2009 years. The following Position Paper originally appeared: JASH. 2008;2(6):484-494. Hypertension complicates 5% to 7% of all pregnancies. A subset of preeclampsia, characterized by new-onset hypertension, proteinuria, and multisystem involvement, is responsible for substantial maternal and fetal morbidity and is a marker for future cardiac and metabolic disease. This American Society of Hypertension, Inc (ASH) position paper summarizes the clinical spectrum of hypertension in pregnancy, focusing on preeclampsia. Recent research breakthroughs relating to etiology are briefly reviewed. Topics include classification of the different forms of hypertension during pregnancy, status of the tests available to predict preeclampsia, and strategies to prevent preeclampsia and to manage this serious disease. The use of antihypertensive drugs in pregnancy, and the prevention and treatment of the convulsive phase of preeclampsia, eclampsia, with intravenous magnesium sulfate is also highlighted. Of special note, this guideline article, specifically requested, reviewed, and accepted by ASH, includes solicited review advice from the American College of Obstetricians and Gynecologists.

Spontaneous preterm birth and small for gestational age infants in women who stop smoking early in pregnancy: prospective cohort study

OBJECTIVES

To compare pregnancy outcomes between women who stopped smoking in early pregnancy and those who either did not smoke in pregnancy or continued to smoke.

DESIGN

Prospective cohort study.

SETTING

Auckland, New Zealand and Adelaide, Australia.

PARTICIPANTS

2504 nulliparous women participating in the Screening for Pregnancy Endpoints (SCOPE) study grouped by maternal smoking status at 15 (+/-1) week's gestation.

MAIN OUTCOME MEASURES

Spontaneous preterm birth and small for gestational age infants (birth weight <10th customised centile). We compared odds of these outcomes between stopped smokers and non-smokers, and between current smokers and stopped smokers, using logistic regression, adjusting for demographic and clinical risk factors.

RESULTS

80% (n=1992) of women were non-smokers, 10% (n=261) had stopped smoking, and 10% (n=251) were current smokers. We noted no differences in rates of spontaneous preterm birth (4%, n=88 v 4%, n=10; adjusted odds ratio 1.03, 95% confidence interval l0.49 to 2.18; P=0.66) or small for gestational age infants (10%, n=195 v 10%, n=27; 1.06, 0.67 to 1.68; P=0.8) between non-smokers and stopped smokers. Current smokers had higher rates of spontaneous preterm birth (10%, n=25 v 4%, n=10; 3.21, 1.42 to 7.23; P=0.006) and small for gestational age infants (17%, n=42 v 10%, n=27; 1.76, 1.03 to 3.02; P=0.03) than stopped smokers.

CONCLUSION

In women who stopped smoking before 15 weeks' gestation, rates of spontaneous preterm birth and small for gestational age infants did not differ from those in non-smokers, indicating that these severe adverse effects of smoking may be reversible if smoking is stopped early in pregnancy.

Is the use of donor sperm associated with a higher incidence of preeclampsia in women who achieve pregnancy after intrauterine insemination?

OBJECTIVE

To evaluate the incidence of preeclampsia after intrauterine insemination (IUI) with either donor's or partner's sperm in women with primary infertility.

DESIGN

Retrospective cohort study.

SETTING

Tertiary referral center.

PATIENTS

Between January 1999 and December 2006, 823 women who achieved pregnancy after IUI and delivered at > or =24 weeks of gestation were reviewed. Only women with primary infertility and no known medical disorders were included. On the basis of the available outcome data, the final analysis was performed in 713 pregnancies (438 pregnancies using donor's sperm and 275 pregnancies using partner's sperm).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The incidence of preeclampsia.

RESULT(S)

The incidence of preeclampsia in pregnancies resulting from donor sperm was higher than in the partner insemination group: 10.9% (48/438) versus 7.2% (20/275), respectively (difference, 3.7; 95% confidence interval -0.8 to +7.8). Logistic regression was performed controlling for the following parameters: type of sperm, number of previous cycles, and number of babies. In the final model, the variables that significantly predicted the risk of preeclampsia were the type of sperm used for insemination and the number of previous IUI cycles performed. The fewer cycles that were performed, the higher the incidence of preeclampsia that was observed.

CONCLUSION(S)

IUI with donor sperm appears to increase the incidence of preeclampsia when pregnancy is achieved. A protective effect of multiple cycles appears also to be present in this respect.

Diagnostic accuracy of urinary spot protein:creatinine ratio for proteinuria in hypertensive pregnant women: systematic review

OBJECTIVE

To review the spot protein:creatinine ratio and albumin:creatinine ratio as diagnostic tests for significant proteinuria in hypertensive pregnant women.

DESIGN

Systematic review.

DATA SOURCES

Medline and Embase, the Cochrane Library, reference lists, and experts. Review methods Literature search (1980-2007) for articles of the spot protein:creatinine ratio or albumin:creatinine ratio in hypertensive pregnancy, with 24 hour proteinuria as the comparator.

RESULTS

13 studies concerned the spot protein:creatinine ratio (1214 women with primarily gestational hypertension). Nine studies reported sensitivity and specificity for eight cut-off points, median 24 mg/mmol (range 17-57 mg/mmol; 0.15-0.50 mg/mg). Laboratory assays were not well described. Diagnostic test characteristics were recalculated for a cut-off point of 30 mg/mmol. No significant heterogeneity in cut-off points was found between studies over a range of proteinuria. Pooled values gave a sensitivity of 83.6% (95% confidence interval 77.5% to 89.7%), specificity of 76.3% (72.6% to 80.0%), positive likelihood ratio of 3.53 (2.83 to 4.49), and negative likelihood ratio of 0.21 (0.13 to 0.31) (nine studies, 1003 women). Two studies of the spot albumin:creatinine ratio (225 women) found optimal cut-off points of 2 mg/mmol for proteinuria of 0.3 g/day or more and 27 mg/mmol for albuminuria.

CONCLUSION

The spot protein:creatinine ratio is a reasonable "rule-out" test for detecting proteinuria of 0.3 g/day or more in hypertensive pregnancy. Information on use of the albumin:creatinine ratio in these women is insufficient.

Regulation of UDP-glucuronosyltransferase (UGT) 1A1 by progesterone and its impact on labetalol elimination

The authors recently reported the increased oral clearance of labetalol in pregnant women. To elucidate the mechanism of the elevated oral clearance, it was hypothesized that female hormones, at the high concentrations attainable during pregnancy, enhance hepatic metabolism of labetalol. Labetalol glucuronidation, which is the major elimination pathway of labetalol, was characterized by screening six recombinant human UGTs (UGT1A1, 1A4, 1A6, 1A9, 2B4, and 2B7) for their capacity to catalyse labetalol glucuronidation. The effect of female hormones (progesterone, oestradiol, oestriol, or oestrone) on the promoter activities of relevant UDP glucuronosyltransferases (UGT) was investigated using a luciferase reporter assay in HepG2 cells. The involvement of oestrogen receptor alpha (ERalpha) and pregnane X receptor (PXR) was examined by co-transfecting ERalpha- or PXR-constructs. UGT1A1 and UGT2B7 were identified as the major UGT enzymes producing labetalol glucuronides (trace amount of glucuronide conjugate was formed by UGT1A9). The activities of the UGT1A1 promoter containing PXR response elements were enhanced by progesterone, but not by oestrogens, indicating PXR-mediated induction of UGT1A1 promoter activity by progesterone. Results from semi-quantitative real-time polymerase chain reaction (PCR) assays are consistent with the above findings. This effect of progesterone on UGT1A1 promoter activities was concentration dependent. Promoter activities of UGT2B7 were not affected by either oestrogens or progesterone. The results suggest a potential role for progesterone in regulating labetalol elimination by modulating the expression of UGT1A1, leading to enhanced drug metabolism during pregnancy.

Altered angiogenesis in preeclampsia: evaluation of a new test system for measuring placental growth factor

BACKGROUND

Decreased concentrations of the circulating angiogenic factors, free placental growth factor (PLGF) and free vascular endothelial growth factor (VEGF), and increased concentrations of the anti-angiogenic factor, soluble fms-like tyrosine kinase 1 (sFLT-1) have been observed during clinical preeclampsia. We established a new PLGF-ELISA kit for the measurement of PLGF in sera. In the present study, we demonstrated the assay characteristics by measurement of PLGF expression in normal and preeclamptic pregnancies as compared to an established research kit.

METHODS

Blood samples were taken from 64 women with singleton uncomplicated pregnancies for longitudinal measurement of PLGF in the course of pregnancy. In 30 preeclamptic patients, serum levels of PLGF and sFLT-1 were measured by Human PLGF-ELISA and Human sVEGF R1 ELISA according to the described test principles. The assay characteristics of the new PLGF-ELISA were determined and the results were compared to those performed with an available research kit.

RESULTS

The PLGF concentration in normal pregnancies showed a steady increase starting at the beginning of the second trimester with a peak at 28-32 weeks and a consistent decline thereafter. The preeclamptic pregnancies had significant lower serum concentrations of PLGF and significant higher serum concentrations of sFLT-1 as compared to the non-preeclamptic pregnancies. All the measured assay characteristics fulfilled the required specifications. Comparison of the values of the new PLGF-ELISA and the established research kit resulted in a correlation coefficient of 0.921.

CONCLUSIONS

Our results support the hypothesis that an imbalance between factors promoting angiogenesis, such as PLGF, and factors antagonizing angiogenesis, such as sFLT-1, has a fundamental role in the pathogenesis of preeclampsia. The new established ELISA test can be considered reliable and it offers many advantages. As it is authorized for routine diagnostic testing, it may offer new possibilities in the prediction of preeclampsia in clinical routine.

Risk factors for preeclampsia in multiparous women: primipaternity versus the birth interval hypothesis

INTRODUCTION

To determine whether the risk of preeclampsia in multiparous women with a previous normal pregnancy is related to changing paternity or to prolonged birth interval, a retrospective study was conducted at the Lyell McEwin Health Service (University of Adelaide).

METHODS

The study included all multiparous women known to the hospital because of their preceding 1st delivery in the same hospital followed by their 2nd and/or 3rd ongoing pregnancy resulting in a delivery in the period 2001 - 2003. Case records were analyzed for birth interval, pregnancy interval, paternity and recognized risk factors such as booking weight and smoking. For the analysis both the International Society for the Study of Hypertension in Pregnancy (ISSHP) definition and the more recently introduced classification by the Australian Society for the Study of Hypertension in Pregnancy (ASSHP) were used.

RESULTS

In the 656 women in this study cohort, 148 (26.2%) women had a different partner in their 2nd and/or 3rd ongoing pregnancy. Using the ISSHP definition for preeclampsia, changing partners had an odds ratio (OR) of 1.304 (95% CI 0.43 - 3.99); using ASSHP criteria an OR of 1.556 (95% CI 0.6506 - 3721); and looking at the combined group of pregnancy-induced hypertensive disorders an OR of 1.99 (95% CI 1.01 - 3.89). A longer birth interval if anything was associated with a lower risk of preeclampsia (non-significant), whatever definition was used. Also the inter-pregnancy interval did not show a consistent relation with the risk for developing a hypertensive complication.

CONCLUSIONS

The results of this study on risk factors for preeclampsia in multiparous women appear to be in line with the primipaternity hypothesis, but are in direct contrast with the so-called birth interval hypothesis.

An International Benchmarking Collaboration: Measuring Outcomes for the Hypertensive Disorders of Pregnancy

OBJECTIVE

To implement a set of clinical indicators to benchmark outcomes for women suffering from the hypertensive disorders of pregnancy.

METHODS

Seven clinical indicators were designed and applied retrospectively to data collected from two tertiary referral centres, Royal Prince Alfred Hospital, Sydney, Australia and British Columbia Women's Hospital and Health Centre, Vancouver BC, for all women coded as hypertensive during pregnancy under the International Classification of Disease (ICD-10) coding system in the years 2002-2004. Diagnostic categories were assigned using the Australasian Society for the Study of Hypertension in Pregnancy criteria, expressed in equivalent Canadian terms drawn from the Report of the Canadian Hypertension Society Consensus. Comparisons were made using the established clinical indicators. Data analysis using chi-square comparison was performed with significance set at P < 0.05. Seven outcome measures of maternal and neonatal mortality and morbidity were compared.

RESULTS

Significant areas of difference between the two tertiary referral centres were seen in birth weights below the 10th centile (RPA 11% vs. BCW 20%; P < 0.05) and below the 3rd centile (RPA 1.5% vs. BCW 7.5%; P < 0.001). There were significantly more episodes of maternal pulmonary edema at BCW than at RPA (0.1% and 1.2%, respectively; P < 0.001).

CONCLUSION

Between similar centres, clinically significant differences in outcomes for HDP were identified. Further evaluation of differences may lead to analysis of possible contributors such as expectant versus urgent delivery management policies, rigidity of blood pressure control, and choice of antihypertensive drug.

A randomised comparison of hydralazine and mini-bolus diazoxide for hypertensive emergencies in pregnancy: The PIVOT trial

AIMS

Diazoxide is one of few available agents for treatment of hypertensive emergencies in pregnancy. From previous studies, there is a question concerning safety after moderate-dose administration caused episodes of hypotension. Rapid control of severe hypertension is necessary to reduce maternal morbidity, for example, stroke and placental abruption. This study was designed to compare the efficacy of mini-bolus diazoxide with intravenous (i.v.) hydralazine.

DESIGN

A randomised controlled trial.

SETTING

Tertiary referral maternity hospital, Royal Prince Alfred Women and Babies, Sydney Australia.

POPULATION

Antenatal and postnatal women with severe hypertension.

METHODS

One hundred and twenty-four hypertensive women were randomised to either i.v. hydralazine (5 mg doses) or mini-bolus diazoxide (15 mg doses).

PRIMARY OUTCOME MEASURE

Achievement of target blood pressure reduction; secondary measures included requirement for Caesarean section because of fetal deterioration as determined by non-reassuring cardiotocograph (CTG).

RESULTS

Reduction in systolic and diastolic blood pressure was 34 min for hydralazine and 19 min for diazoxide (P < 0.001). There were no episodes of hypotension after diazoxide and one after hydralazine (after epidural). Episodes of persistent severe hypertension were more common with hydralazine (38%) than with diazoxide (16%), P < 0.01. The Caesarean section rate for no-reassuring CTG was no different between the two groups. Neonatal outcomes were similar.

CONCLUSION

Diazoxide and hydralazine are safe and effective antihypertensives, showing a controlled and comparable blood pressure reduction in women with hypertensive emergencies in pregnancy. The mini-bolus doses of 15 mg of diazoxide did not precipitate maternal hypotension as previously described and reduces episodes of persistent severe hypertension.

Immunogenetics of pregnancy: role of a 14-bp deletion in the maternal HLA-G gene in primiparous pre-eclamptic Brazilian women

The etiology and pathogenesis of pre-eclampsia (PE) involve a combination of maternal-fetal genetic and immunologic factors. The immunologic maladaptation theory of PE predicts that the maternal immune system does not tolerate the semi-allogeneic fetus. Human leukocyte antigen-G (HLA-G) is expressed in some types of immune cells as well as in the fetal-maternal interface by trophoblasts, playing an immunoregulatory role. Here we have evaluated a 14-bp deletion polymorphism in the 3'-untranslated region of exon 8 of HLA-G gene in pregnant PE women and controls. HLA-G genotypes in both control and PE women were in Hardy-Weinberg equilibrium. The healthy pregnant and PE women had similar genotype frequencies (p = 0.789). This was similarly observed when PE women were subgrouped accordingly to severity of disease (p = 0.646). However, the primiparous PE women presented a tendency toward higher frequency of the 14-bp deletion allele (0.442) compared with the primiparous healthy women (0.286), p = 0.09. Our data suggest that the maternal 14-bp deletion of HLA-G is not associated with the risk for PE but that it could affect the development of PE in primiparous women.

The Control of Hypertension In Pregnancy Study pilot trial

OBJECTIVE

To determine whether 'less tight' (versus 'tight') control of nonsevere hypertension results in a difference in diastolic blood pressure (dBP) between groups.

DESIGN

Randomised controlled trial (ISRCTN#57277508).

SETTING

Seventeen obstetric centres in Canada, Australia, New Zealand, and UK.

POPULATION

Inclusion: pregnant women, dBP 90-109 mmHg, pre-existing/gestational hypertension; live fetus(es); and 20-33(+6) weeks. Exclusion: systolic blood pressure > or = 170 mmHg and proteinuria, contraindication, or major fetal anomaly.

METHODS

Randomisation to less tight (target dBP, 100 mmHg) or tight (target dBP, 85 mmHg) blood pressure control.

MAIN OUTCOME MEASURES

Primary: mean dBP at 28, 32 and 36 weeks. Secondary: clinician compliance and women's satisfaction. Other: serious perinatal and maternal complications.

RESULTS

A total of 132 women were randomised to less tight (n = 66; seven had no study visit) or tight control (n= 66; one was lost to follow up; seven had no study visit). Mean dBP was significantly lower with tight control: -3.5 mmHg, 95% credible interval (-6.4, -0.6). Clinician compliance was 79% in both groups. Women were satisfied with their care. With less tight (versus tight) control, the rates of other treatments and outcomes were the following: post-randomisation antenatal antihypertensive medication use: 46 (69.7%) versus 58 (89.2%), severe hypertension: 38 (57.6%) versus 26 (40.0%), proteinuria: 16 (24.2%) versus 20 (30.8%), serious maternal complications: 3 (4.6%) versus 2 (3.1%), preterm birth: 24 (36.4%) versus 26 (40.0%), birthweight: 2675 +/- 858 versus 2501 +/- 855 g, neonatal intensive care unit (NICU) admission: 15 (22.7%) versus 22 (34.4%), and serious perinatal complications: 9 (13.6%) versus 14 (21.5%).

CONCLUSION

The CHIPS pilot trial confirms the feasibility and importance of a large definitive trial to determine the effects of less tight control on serious perinatal and maternal complications.

Pre-eclampsia: contribution of maternal constitutional factors and the consequences for cardiovascular health

1. Pre-eclampsia is a serious complication of pregnancy that is potentially life threatening for both the mother and baby. It encompasses a number of abnormalities that may be present in other clinical conditions. 2. A placenta is essential for the development of pre-eclampsia and can be important in the pathogenesis of pre-eclampsia. Normal pregnancy is associated with remodelling of the maternal spiral arteries, which deliver blood to the placental villous space. Remodelling involves invasion by placental cytotrophoblasts that cause the maternal spiral arteries to lose their smooth muscle and become capacitance vessels; this process, known as placentation, is complete by 20 weeks of pregnancy. Poor placentation is associated with small-for-gestational-age fetuses and some cases of pre-eclampsia. It is thought that poor placentation can result in a hypoxic placenta that releases 'toxic substances' into the maternal circulation, contributing to the maternal syndrome. A number of candidate 'toxic substances' have been proposed, but none is universally raised in pre-eclampsia. 3. Although the placenta is necessary for the development of pre-eclampsia, the extent to which placental abnormalities contribute to the condition varies. It is becoming apparent that maternal constitutional factors may also be important in this syndrome. Underlying hypertension, diabetes and obesity strongly predispose to pre-eclampsia. However, a continuum of risk may exist for blood pressure, bodyweight, glucose and lipids, which, in combination with each other and some degree of placental abnormalities, may lead to the development of pre-eclampsia. 4. The present review will focus on the maternal constitutional factors that define the metabolic syndrome and examine their contribution to pre-eclampsia and the long-term consequences for cardiovascular health.

Maternal serum activin A and the prediction of intrauterine growth restriction

BACKGROUND

Differentiating between the small healthy fetus and the high risk growth restricted fetus remains a significant obstetric challenge. It has been previously shown that maternal activin A levels are increased in association with fetal growth restriction.

AIM

To evaluate maternal serum activin A as a marker of fetal growth restriction.

METHODS

Prospective cohort study of 62 women referred for fetal assessment because of a clinical suspicion of a small for gestation fetus. Maternal serum levels of activin A were measured with an ELISA.

RESULTS

Activin A levels, expressed as median (95% CI) MoMs, were similar in the women with a normal-sized fetus and in those with a healthy small for gestational age fetus, 1.14 (95% CI 1.0-1.5) and 1.31 (95% CI 0.8-2.1), respectively (P = 0.97). Compared to the women with a normal-sized fetus or a healthy small fetus, activin A levels were significantly elevated in the women who had an intrauterine fetal growth restriction fetus 2.37 (95% CI 1.6-3.7; P = 0.01 compared to normal and P = 0.04 compared to healthy small).

CONCLUSIONS

These data confirm that circulating activin A is increased in association with fetal growth restriction. However, a single blood sample for activin A will not efficiently discern between healthy and compromised small fetuses.

Mechanisms of Disease: pre-eclampsia

Pre-eclampsia, a syndrome of pregnant women, is one of the leading causes of maternal and fetal morbidity and mortality. Despite active research, the etiology of this disorder remains an enigma. Recent work has, however, provided promising explanations for the causation of the disorder and some of its phenotypes. Evidence indicates that the symptoms of hypertension and proteinuria, upon which the diagnosis of pre-eclampsia is based, have several underlying causes. Nevertheless, the treatment of pre-eclampsia has not changed significantly in over 50 years. This review describes the most recent insights into the pathophysiology of pre-eclampsia from both basic and clinical research, and attempts to provide a unifying hypothesis to reconcile the abnormalities at the feto-placental level and the clinical features of the maternal syndrome. The novel findings outlined in this review provide a rationale for potential future prophylactic and therapeutic interventions for pre-eclampsia.

Uric acid is as important as proteinuria in identifying fetal risk in women with gestational hypertension

Gestational hypertension is differentiated into higher and lower risk by the presence or absence of proteinuria. We asked if hyperuricemia, a common finding in pregnancy hypertension, might also be an indicator of increased risk. We examined fetal outcome data from 972 pregnancies collected from 1997 to 2002 in a nested case-control study. Participants were nulliparous with no known medical complications. The frequency of preterm birth, the duration of pregnancy, frequency of small-for-gestational-age infants, and birth weight centile were determined for pregnancies assigned to 8 categories by the presence or absence of combinations of hypertension, hyperuricemia, and proteinuria. In women with gestational hypertension, hyperuricemia was associated with shorter gestations and smaller birth weight centiles and increased risk of preterm birth and small-for-gestational-age infants. Hyperuricemia increased the risk of these outcomes in the presence or absence of proteinuria. Risk was also increased in a small group of women with hyperuricemia and proteinuria without hypertension. Women with only hypertension and hyperuricemia have similar or greater risk as women with only hypertension and proteinuria. Those with hypertension, proteinuria, and hyperuricemia have greater risk than those with hypertension and proteinuria alone. The risk of these outcomes increased with increasing uric acid. Hyperuricemia is at least as effective as proteinuria at identifying gestational hypertensive pregnancies at increased risk. Uric acid should be reexamined for clinical and research utility.