Management of hypertensive disorders during pregnancy: summary of NICE guidance
BMJ 2010; 341 doi: https://doi.org/10.1136/bmj.c2207 (Published 25 August 2010) Cite this as: BMJ 2010;341:c2207
- Cristina Visintin, project manager1,
- Moira A Mugglestone, director of guideline development 1,
- Muhammad Q Almerie, foundation house officer 12,
- Leo M Nherera, health economist1,
- David James, clinical codirector1,
- Stephen Walkinshaw, consultant in maternal and fetal medicine3
- on behalf of the Guideline Development Group
- 1National Collaborating Centre for Women’s and Children’s Health, London W1T 2QA
- 2North Yorkshire and East Coast Foundation School, Diana, Princess of Wales Hospital, Grimsby DN33 2BA
- 3Liverpool Women’s Hospital, Liverpool L8 7SS
- Correspondence to: M A Mugglestone mmugglestone{at}ncc-wch.org.uk
Why read this summary?
Hypertensive disorders of pregnancy cover a spectrum of conditions, including chronic (pre-existing) hypertension, pre-eclampsia, and gestational hypertension (box 1). These conditions are associated with increased perinatal mortality and morbidity. Hypertensive disorders cause one in 50 stillbirths in normal babies and 10% of all preterm births. They contribute to a third of cases of severe maternal morbidity.1 Pre-eclampsia is one of the most common causes of maternal death in the United Kingdom.2 This article summarises the most recent recommendations from the National Institute for Health and Clinical Excellence (NICE) on how to manage hypertensive disorders during pregnancy.3
Box 1 Definitions
Chronic hypertension: hypertension present at booking visit or before 20 weeks’ gestation, or being treated at time of referral to maternity services; can be primary or secondary in aetiology
Clinically relevant proteinuria: more than 300 mg protein in a 24 hour urine collection or more than 30 mg/mmol in a spot urinary protein:creatinine sample
HELLP syndrome: haemolysis, elevated liver enzymes, and low platelet count
Gestational hypertension: new hypertension presenting after 20 weeks’ gestation without clinically relevant proteinuria
Mild hypertension: diastolic blood pressure 90-99 mm Hg, systolic blood pressure 140-149 mm Hg
Moderate hypertension: diastolic blood pressure 100-109 mm Hg, systolic blood pressure 150-159 mm Hg
Pre-eclampsia: new hypertension presenting after 20 weeks’ gestation with clinically relevant proteinuria
Severe hypertension: diastolic blood pressure 110 mm Hg or greater, systolic blood pressure 160 mm Hg or greater
Severe pre-eclampsia: pre-eclampsia with severe hypertension or with symptoms, biochemical abnormalities, or haematological impairment (or any combination thereof)
Recommendations
NICE recommendations are based on systematic reviews of best available evidence and explicit consideration of cost effectiveness. When minimal evidence is available, recommendations are based on the Guideline Development Group’s experience and opinion of what constitutes good practice. Evidence levels for the recommendations are given in italic in square brackets.
Reducing the risk of hypertensive disorders in pregnancy
Advise pregnant women of their risk of developing hypertensive disorders during pregnancy (in particular pre-eclampsia; see box 2) and of the need to seek immediate advice from a healthcare professional if they experience symptoms of pre-eclampsia (severe headache; problems with vision, such as blurring or flashing before the eyes; severe pain just below the ribs; vomiting; sudden swelling of face, hands, or feet).
Box 2 Risk factors for pre-eclampsia
Moderate risk
Age 40 years or more
First pregnancy
Multiple pregnancy
Interval since last pregnancy of more than 10 years
Body mass index of 35 or more at presentation
Family history of pre-eclampsia
High risk
Chronic hypertension
Chronic kidney disease
Hypertensive disease during a previous pregnancy
Diabetes
Autoimmune disease
Advise women with at least one high risk factor for pre-eclampsia or at least two moderate risk factors for pre-eclampsia (box 2) to take 75 mg of aspirin daily from 12 weeks until the birth of the baby. [Based on high quality evidence from meta-analyses of randomised controlled trials and a health economic model developed for the guideline]
Although several drugs (nitric oxide donors, progesterone, diuretics, and low molecular weight heparin) and vitamin and nutrient supplements (such as vitamin C, vitamin E, folic acid, magnesium, fish oils, algal oils, and garlic) have been studied as preventive treatments for hypertensive disorders, these have not shown benefit and should not be given for this purpose. The evidence for added calcium in the prevention of hypertensive disorders is conflicting and confusing, and more research is needed in this area.
Chronic hypertension
Preconception
Tell women taking angiotensin converting enzyme inhibitors and angiotensin II receptor blockers that taking these drugs during pregnancy increases the risk of congenital abnormalities, and that they should discuss other antihypertensive treatments with their healthcare professional if they are planning pregnancy. [Based on moderate quality evidence from observational studies]
Tell women taking chlorothiazide diuretics that taking these drugs during pregnancy increases the risk of congenital abnormalities and neonatal complications, and that they should discuss other antihypertensive treatments with their healthcare professional if they are planning pregnancy.
Reassure women taking antihypertensive treatments other than angiotensin converting enzyme inhibitors, angiotensin II receptor blockers, or chlorothiazide diuretics that the limited evidence available has not shown an increased risk of congenital malformation with such treatments.
Antenatal care
Antihypertensive treatment should be offered but be dependent on pre-existing treatment, side effect profiles, and teratogenicity.
If women taking angiotensin converting enzyme inhibitors or angiotensin II receptor blockers become pregnant, stop these drugs and offer alternatives.
Aim to keep blood pressure lower than 150/100 mm Hg in pregnant women with uncomplicated chronic hypertension but do not lower diastolic blood pressure below 80 mm Hg. [Based on high quality evidence from randomised controlled trials and a meta-regression of such trials]
Schedule additional antenatal consultations on the basis of the woman and her baby’s needs.
Do not offer birth before 37 weeks’ gestation if blood pressure is lower than 160/110 mm Hg, with or without antihypertensive treatment.
New onset hypertension during pregnancy
Assessment of proteinuria
To diagnose pre-eclampsia and distinguish it from gestational hypertension, use an automated reagent strip reading device or spot urinary protein:creatinine ratio for estimating proteinuria in secondary care.
If an automated reagent strip reading device is used to detect proteinuria and a result of 1+ or more is obtained, use a spot protein:creatinine ratio or 24 hour urine collection to quantify proteinuria.
Diagnose clinically relevant proteinuria if the urinary protein:creatinine ratio is greater than 30 mg/mmol or a validated 24 hour urine collection shows greater than 300 mg protein.
Where 24 hour urine collection is used to quantify proteinuria, a recognised method of evaluating completeness of the sample should be used.
[All four recommendations are based on high quality evidence from systematic reviews of diagnostic test accuracy studies, further diagnostic test accuracy studies, and health economic models developed for the guideline]
Management of gestational hypertension
Offer an integrated package of care covering assessment in hospital by a healthcare professional trained in managing hypertensive disorders; possible hospital admission; treatment; and monitoring of blood pressure, proteinuria, and blood tests as indicated in table 1⇓. [Based on moderate quality evidence from randomised controlled trials and observational studies]
Management of gestational hypertension
Management of pre-eclampsia
Assess women with pre-eclampsia at each consultation; assessment should be performed by a healthcare professional trained in the management of hypertensive disorders of pregnancy.
Offer an integrated package of care covering admission to hospital; treatment; and monitoring of blood pressure, proteinuria, and blood tests as indicated in table 2⇓. [Based on moderate quality evidence from randomised controlled trials and observational studies]
Manage pregnancy conservatively (do not plan same day delivery of the baby) until 34 weeks’ gestation.
Consultant obstetric staff should document in the woman’s notes maternal and fetal biochemical, haematological, and clinical thresholds for birth before 34 weeks’ gestation and write a plan for fetal monitoring during birth. [Based on the experience and opinion of the guideline development group]
Management of pre-eclampsia
Fetal monitoring
In women with chronic hypertension, carry out ultrasound assessment of fetal growth and amniotic fluid volume and umbilical artery Doppler velocimetry between 28 and 30 weeks’ gestation and between 32 and 34 weeks’ gestation. If results are normal, do not repeat after 34 weeks’ gestation, unless clinically indicated.
In women with mild or moderate gestational hypertension diagnosed at less than 34 weeks’ gestation, carry out ultrasound assessment of fetal growth and amniotic fluid volume and umbilical artery Doppler velocimetry. If results are normal, do not repeat after 34 weeks’ gestation, unless clinically indicated.
In women with severe gestational hypertension or pre-eclampsia, carry out cardiotocography at diagnosis. If conservative management is planned, carry out ultrasound assessment of fetal growth and amniotic fluid volume and umbilical artery Doppler velocimetry at diagnosis; if results are normal, do not repeat more than every two weeks. Do not repeat cardiotocography more than weekly if results of all fetal monitoring are normal.
Intrapartum care
During labour, measure blood pressure hourly in women with mild or moderate hypertension, and continually in women with severe hypertension.
Continue antenatal antihypertensive treatment during labour.
Determine the need for haematological and biochemical tests during labour in women with mild or moderate hypertension using the same criteria as for the antenatal period (even if regional analgesia is being considered).
If low dose epidural analgesia or combined spinal epidural analgesia is needed in women with severe pre-eclampsia, do not preload with intravenous fluids.
Medical management of severe hypertension or severe pre-eclampsia in critical care
The full guideline includes recommendations on criteria for referral to critical care, management of severe hypertension (including antihypertensive treatment and blood pressure measurement), anticonvulsants, corticosteroids (use betamethasone for fetal lung maturation but do not use betamethasone or dexamethasone for treatment of HELLP syndrome (box 1)), and fluid balance and volume expansion.
Choose the mode of birth (induction of labour or caesarean section) according to the clinical circumstances and the woman’s preference.
Postnatal care and follow-up care
The full guideline includes recommendations on antihypertensive treatment and blood pressure measurement in the postnatal period.
Tell women that labetalol, nifedipine, enalapril, captopril, atenolol, and metoprolol have no known adverse effects on babies receiving breast milk.
Tell women that there is insufficient evidence on the safety of angiotensin II receptor blockers, amlodipine, and angiotensin converting enzyme inhibitors other than enalapril and captopril in babies receiving breast milk.
Offer a medical review at the postnatal review (six to eight weeks after the birth). [Based on the experience and opinion of the guideline development group]
At transfer to community care tell women who have had gestational hypertension or pre-eclampsia that they have an increased risk of these conditions occurring in future pregnancies [Based on high quality evidence from observational studies] and an increased risk of developing high blood pressure and its complications in later life.
Overcoming barriers
Management of hypertensive disorders in pregnancy is thought to vary considerably, with many practices reflecting tradition rather than being evidence based. The recommendations and the supporting evidence should give healthcare professionals confidence to reduce the frequency of unnecessary tests and assessments in women with mild or moderate disease, yet emphasise an escalating approach to care that is centred more on individual women. The guidance may reduce interventions that result in morbidity, such as preterm birth, and may better target interventions that are likely to benefit the woman and her baby. Such changes are more likely to be adopted by clinicians, as are the many cost saving aspects of this guidance. Informed dialogue is another powerful driver of change: emphasising prevention, increasing information for women themselves, and increasing awareness of signs and symptoms from existing NICE guidance for routine antenatal care4 should empower pregnant women to have such dialogue with their healthcare professionals.
Further information on the guidance
Background
National guidance already exists for care of women with severe pre-eclampsia or eclampsia and on screening for hypertensive disorders during pregnancy.4 5 However, until now there has been no comprehensive guidance on assessment and care after a diagnosis of new onset hypertension or for women with chronic hypertension. This guideline builds on and complements existing NICE guidance for routine antenatal, intrapartum, and postnatal care,4 6 7 and management of hypertension outside of pregnancy.8
Methods
This guidance was developed by the National Collaborating Centre for Women’s and Children’s Health in accordance with NICE guideline development methods (www.nice.org.uk/guidelinesmanual). A guideline development group was established by the National Collaborating Centre for Women’s and Children’s Health, which incorporated healthcare professionals, women with experience of hypertensive disorders during pregnancy, and experts in guideline methodology. The Guideline Development Group identified relevant clinical questions, collected and appraised clinical evidence, and evaluated the cost effectiveness of proposed interventions where possible. The draft guideline underwent a rigorous reviewing process where stakeholder organisations were invited to comment; all comments were taken into consideration when producing the final version of the guideline.
NICE has produced four different version of the guideline: a full version containing all the evidence, the process undertaken to develop the recommendations, and all the recommendations; a quick reference guide; a version containing a list of all the recommendations, known as the “NICE guideline;” and a version for patients and the public. All these versions are available from the NICE website (www.nice.org.uk/CG107). Further updates of the guidance will be produced as part of the NICE guideline development programme.
Future research
How clinically effective and cost effective is calcium supplementation in preventing pre-eclampsia in women at moderate risk or high risk of pre-eclampsia?
How should clinically relevant proteinuria be defined in women with hypertension in pregnancy?
What is the role of assessing haematological or biochemical parameters at diagnosis of gestational hypertension and during subsequent monitoring?
When should women with mild or moderate pre-eclampsia give birth?
How safe are commonly used antihypertensive agents in breast feeding?
Notes
Cite this as: BMJ 2010;340:c2207
Footnotes
This is one of a series of BMJ summaries of new guidelines based on the best available evidence; they highlight important recommendations for clinical practice, especially where uncertainty or controversy exists
The members of the Guideline Development Group are Chris Barry, Rachel Fielding, Pauline Green, Jane Hawdon, David James (from December 2009), Rajesh Khanna (until May 2009), Surbhi Malhotra, Fiona Milne, Susan Mitchinson, Moira Mugglestone (from May 2009), Lynda Mulhair, Leo Nherera, Adam North, Derek Tuffnell, James Walker, Stephen Walkinshaw (chair), David Williams, and Martin Whittle (until December 2009).
Contributors: CV and MAM wrote the initial draft of the article using material produced collectively by the guideline development group and revised the draft after receipt of comments from MQA, LMN, DJ, SW, and the series editor. All authors approved the final version for publication. MAM is guarantor.
Funding: The National Collaborating Centre for Women’s and Children’s Health was commissioned and funded by the National Institute for Health and Clinical Excellence to write this summary.
Competing interests: All authors have completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare that: (1) CV, MAM, LMN, and DJ have support from the National Institute for Health and Clinical Excellence for the submitted work; (2) They have no relationships with companies that might have an interest in the submitted work; (3) Their spouses, partners, and children have no financial relationships that may be relevant to the submitted work; and (4) They have no non-financial interests that may be relevant to the submitted work.
Provenance and peer review: Commissioned; not externally peer reviewed.