Hypertension in Pregnancy: Diagnosis and Management in Secondary Care Settings

Overview

This specialist secondary care Guidelines summary covers diagnosing and managing hypertension (high blood pressure), including pre-eclampsia, during pregnancy. It also includes advice for women with hypertension who wish to conceive, and women who have had a pregnancy complicated by hypertension. It aims to improve care during pregnancy for women and their babies.

Please refer to the full guideline for information on reducing the risk of hypertensive disorders in pregnancy.

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Assessment of Proteinuria in Hypertensive Disorders of Pregnancy

• Interpret proteinuria measurements for pregnant women in the context of a full clinical review of symptoms, signs, and other investigations for pre-eclampsia 
• Use an automated reagent-strip reading device for dipstick screening for proteinuria in pregnant women in secondary care settings
• If dipstick screening is positive (1+ or more), use albumin:creatinine ratio or protein:creatinine ratio to quantify proteinuria in pregnant women
• Do not use first morning urine void to quantify proteinuria in pregnant women
• Do not routinely use 24-hour urine collection to quantify proteinuria in pregnant women
• If using protein:creatinine ratio to quantify proteinuria in pregnant women:
  • use 30 mg/mmol as a threshold for significant proteinuria
  • if the result is 30 mg/mmol or above and there is still uncertainty about the diagnosis of pre-eclampsia, consider re-testing on a new sample, alongside clinical review
• If using albumin:creatinine ratio as an alternative to protein:creatinine ratio to diagnose pre-eclampsia in pregnant women with hypertension:
  • use 8 mg/mmol as a diagnostic threshold
  • if the result is 8 mg/mmol or above and there is still uncertainty about the diagnosis of pre-eclampsia, consider re-testing on a new sample, alongside clinical review. 

Management of Chronic Hypertension in Pregnancy

Pre-pregnancy Advice

• Offer women with chronic hypertension referral to a specialist in hypertensive disorders of pregnancy to discuss the risks and benefits of treatment
• Advise women who take angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers^[A] (ARBs):
  • that there is an increased risk of congenital abnormalities if these drugs are taken during pregnancy
  • to discuss alternative antihypertensive treatment with the healthcare professional responsible for managing their hypertension, if they are planning pregnancy
  • to discuss alternative treatment with the healthcare professional responsible for managing their condition, if ACE inhibitors or ARBs are being taken for other conditions such as renal disease 
• Stop antihypertensive treatment in women taking ACE inhibitors or ARBs if they become pregnant (preferably within 2 working days of notification of pregnancy) and offer alternatives
• Advise women who take thiazide or thiazide-like diuretics:
  • that there may be an increased risk of congenital abnormalities and neonatal complications if these drugs are taken during pregnancy
  • to discuss alternative antihypertensive treatment with the healthcare professional responsible for managing their hypertension, if they are planning pregnancy
• Advise women who take antihypertensive treatments other than ACE inhibitors, ARBs, thiazide or thiazide-like diuretics that the limited evidence available has not shown an increased risk of congenital malformation with such treatments. 

Treatment of Chronic Hypertension

• Offer pregnant women with chronic hypertension advice on:
  • weight management
  • exercise
  • healthy eating
  • lowering the amount of salt in their diet.

Provide this advice in line with the NICE guideline on hypertension in adults: diagnosis and management. 

• Continue with existing antihypertensive treatment if safe in pregnancy, or switch to an alternative treatment, unless:
  • sustained systolic blood pressure is less than 110 mmHg, or
  • sustained diastolic blood pressure is less than 70 mmHg, or
  • the woman has symptomatic hypotension
• Offer antihypertensive treatment to pregnant women who have chronic hypertension and who are not already on treatment if they have:
  • sustained systolic blood pressure of 140 mmHg or higher, or
  • sustained diastolic blood pressure of 90 mmHg or higher
• When using medicines to treat hypertension in pregnancy, aim for a target blood pressure of 135/85 mmHg
• Consider labetalol to treat chronic hypertension in pregnant women Consider nifedipine^[B] for women in whom labetalol is not suitable, or methyldopa if both labetalol and nifedipine^[B] are not suitable. Base the choice on any pre-existing treatment, side-effect profiles, risks (including fetal effects) and the woman's preference 
• Offer pregnant women with chronic hypertension aspirin^[C] 75–150 mg once daily from 12 weeks
• Offer placental growth factor (PlGF)-based testing to help rule out pre-eclampsia between 20 weeks and 36 weeks and 6 days of pregnancy, if women with chronic hypertension are suspected of developing pre-eclampsia. (See the NICE diagnostics guidance on PlGF-based testing to help diagnose suspected pre-eclampsia). 

For recommendations on antenatal appointments, and timing of birth, please refer to the full guideline. 

Postnatal Investigation, Monitoring, and Treatment

• In women with chronic hypertension who have given birth, measure blood pressure:
  • daily for the first 2 days after birth
  • at least once between day 3 and day 5 after birth
  • as clinically indicated if antihypertensive treatment is changed after birth
• In women with chronic hypertension who have given birth:
  • aim to keep blood pressure lower than 140/90 mmHg
  • continue antihypertensive treatment, if required (see Antihypertensive treatment during the postnatal period, including during breastfeeding)
  • offer a review of antihypertensive treatment 2 weeks after the birth, with their GP or specialist
• If a woman has taken methyldopa to treat chronic hypertension during pregnancy, stop within 2 days after the birth and change to an alternative antihypertensive treatment (see Antihypertensive Treatment During the Postnatal Period, including during breastfeeding)
• Offer women with chronic hypertension a medical review 6–8 weeks after the birth with their GP or specialist, as appropriate. 

Management of Gestational Hypertension

Assessment and Treatment of Gestational Hypertension

• In women with gestational hypertension, a full assessment should be carried out in a secondary care setting by a healthcare professional who is trained in the management of hypertensive disorders of pregnancy
• In women with gestational hypertension, take account of the following risk factors that require additional assessment and follow-up:
  • nulliparity
  • age 40 years or older
  • pregnancy interval of more than 10 years
  • family history of pre-eclampsia
  • multi-fetal pregnancy
  • BMI of 35 kg/m² or more
  • gestational age at presentation
  • previous history of pre-eclampsia or gestational hypertension
  • pre-existing vascular disease
  • pre-existing kidney disease
• Offer women with gestational hypertension the tests and treatment listed in Table 1. 

Table 1: Management of Pregnancy With Gestational Hypertension

• Offer PlGF-based testing to help rule out pre-eclampsia in women presenting with suspected pre-eclampsia (for example, with gestational hypertension) between 20 weeks and 36 weeks and 6 days of pregnancy. (See the NICE diagnostics guidance on PlGF-based testing to help diagnose suspected pre-eclampsia)
• Consider labetalol to treat gestational hypertension. Consider nifedipine^[B] for women in whom labetalol is not suitable, and methyldopa if labetalol or nifedipine^[B] are not suitable. Base the choice on side-effect profiles, risk (including fetal effects) and the woman's preferences
• Do not offer bed rest in hospital as a treatment for gestational hypertension. 

For recommendations on timing of birth, postnatal investigation, monitoring, and treatment, refer to the full guideline. 

Management of Pre-eclampsia

Assessing Pre-eclampsia

• Assessment of women with pre-eclampsia should be performed by a healthcare professional trained in the management of hypertensive disorders of pregnancy. 

For more recommendations on assessment of pre-eclampsia, refer to the full guideline. 

Treatment of Pre-eclampsia

• Offer women with pre-eclampsia the tests and treatments listed in Table 2
• For recommendations on fetal assessment, please refer to the full guideline. 

Table 2: Management of Pregnancy with Pre-eclampsia

• Offer labetalol to treat hypertension in pregnant women with pre-eclampsia. Offer nifedipine^[B] for women in whom labetalol is not suitable, and methyldopa if labetalol or nifedipine^[B] are not suitable. Base the choice on any pre-existing treatment, side-effect profiles, risks (including fetal effects) and the woman's preference. 

For recommendations on timing of birth in women with pre-eclmapsia, please refer to the full guideline. 

Postnatal Investigation, Monitoring, and Treatment (Including After Discharge From Critical Care)

Blood Pressure

• In women with pre-eclampsia who did not take antihypertensive treatment and have given birth, measure blood pressure:
  • at least 4 times a day while the woman is an inpatient
  • at least once between day 3 and day 5 after birth
  • on alternate days until normal, if blood pressure was abnormal on days 3–5
• In women with pre-eclampsia who did not take antihypertensive treatment and have given birth, start antihypertensive treatment if blood pressure is 150/100 mmHg or higher 
• Ask women with pre-eclampsia who have given birth about severe headache and epigastric pain each time blood pressure is measured
• In women with pre-eclampsia who took antihypertensive treatment and have given birth, measure blood pressure:
  • at least 4 times a day while the woman is an inpatient
  • every 1–2 days for up to 2 weeks after transfer to community care until the woman is off treatment and has no hypertension 
• For women with pre-eclampsia who have taken antihypertensive treatment and have given birth:
  • continue antihypertensive treatment (see section 1.9 for choice of antihypertensive during the postnatal period)
  • consider reducing antihypertensive treatment if their blood pressure falls below 140/90 mmHg
  • reduce antihypertensive treatment if their blood pressure falls below 130/80 mmHg
• If a woman has taken methyldopa to treat pre-eclampsia, stop within 2 days after the birth and change to an alternative treatment if necessary (see Antihypertensive treatment during the postnatal period, including during breastfeeding)
• Offer women with pre-eclampsia who have given birth transfer to community care if all of the following criteria have been met:
  • there are no symptoms of pre-eclampsia
  • blood pressure, with or without treatment, is 150/100 mmHg or less
  • blood test results are stable or improving
• Write a care plan for women with pre-eclampsia who have given birth and are being transferred to community care that includes all of the following:
  • who will provide follow-up care, including medical review if needed
  • frequency of blood pressure monitoring
  • thresholds for reducing or stopping treatment
  • indications for referral to primary care for blood pressure review
  • self-monitoring for symptoms 
• Offer women who have had pre-eclampsia and who remain on antihypertensive treatment a medical review with their GP or specialist 2 weeks after transfer to community care
• Offer all women who have had pre-eclampsia a medical review with their GP or specialist 6-8 weeks after the birth. 

Haematological and Biochemical Monitoring

• In women who have pre-eclampsia with mild or moderate hypertension, or after step-down from critical care:
  • measure platelet count, transaminases and serum creatinine 48–72 hours after birth or step-down
  • do not repeat platelet count, transaminases or serum creatinine measurements if results are normal at 48–72 hours 
• If biochemical and haematological indices are outside the reference range in women with pre-eclampsia who have given birth, repeat platelet count, transaminases and serum creatinine measurements as clinically indicated until results return to normal 
• In women with pre-eclampsia who have given birth, carry out a urinary reagent-strip test 6–8 weeks after the birth
• Offer women who had pre-eclampsia and still have proteinuria (1+ or more) at 6–8 weeks after the birth a further review with their GP or specialist at 3 months after the birth to assess kidney function
• Consider referring women with an abnormal kidney function assessment at 3 months for a specialist kidney assessment in line with the NICE guideline on chronic kidney disease in adults. 

For recommendations on fetal monitoring and intrapartum care, please refer to the full guideline. 

Medical Management of Severe Hypertension, Severe Pre-eclampsia, or Eclampsia in a Critical Care Setting

Anticonvulsants

• If a woman in a critical care setting who has severe hypertension or severe pre-eclampsia has or previously had an eclamptic fit, give intravenous magnesium sulfate

For a full set of recommendations on anticonvulsants, please refer to the full guideline. 

Antihypertensives

• Treat women with severe hypertension who are in critical care during pregnancy or after birth immediately with 1 of the following:
  • labetalol (oral or intravenous)
  • oral nifedipine^[B] 
  • intravenous hydralazine
• In women with severe hypertension who are in critical care, monitor their response to treatment:
  • to ensure that their blood pressure falls
  • to identify adverse effects for both the woman and the baby
  • to modify treatment according to response
• Consider using up to 500 ml crystalloid fluid before or at the same time as the first dose of intravenous hydralazine in the antenatal period. 

For recommendations on corticosteroids for fetal lung maturation. corticosteroids to manage HELLP syndrome, fluid balance and volume expansion, and caesarean section versus induction of labour, refer to the full guideline. 

Referral to Critical Care

• Refer women with severe hypertension or severe pre-eclampsia to the appropriate critical care setting using the criteria in Table 3. 

Table 3: Clinical Criteria for Choice of Critical Care Level

Antihypertensive Treatment During the Postnatal Period, Including During Breastfeeding

• Advise women with hypertension who wish to breastfeed that their treatment can be adapted to accommodate breastfeeding, and that the need to take antihypertensive medication does not prevent them from breastfeeding. 
• Explain to women with hypertension who wish to breastfeed that:
  • antihypertensive medicines can pass into breast milk
  • most antihypertensive medicines taken while breastfeeding only lead to very low levels in breast milk, so the amounts taken in by babies are very small and would be unlikely to have any clinical effect
  • most medicines are not tested in pregnant or breastfeeding women, so disclaimers in the manufacturer's information are not because of any specific safety concerns or evidence of harm.

Make decisions on treatment together with the woman, based on her preferences. 

• As antihypertensive agents have the potential to transfer into breast milk:
  • consider monitoring the blood pressure of babies, especially those born preterm, who have symptoms of low blood pressure for the first few weeks
  • when discharged home, advise women to monitor their babies for drowsiness, lethargy, pallor, cold peripheries, or poor feeding
• Offer enalapril^[E] to treat hypertension in women during the postnatal period, with appropriate monitoring of maternal renal function and maternal serum potassium
• For women of black African or Caribbean family origin with hypertension during the postnatal period, consider antihypertensive treatment with:
  • nifedipine,^[B] or
  • amlodipine if the woman has previously used this to successfully control her blood pressure
• For women with hypertension in the postnatal period, if blood pressure is not controlled with a single medicine, consider a combination of nifedipine^[B] (or amlodipine) and enalapril.^[E] If this combination is not tolerated or is ineffective, consider either:
  • adding atenolol or labetalol to the combination treatment, or
  • swapping 1 of the medicines already being used for atenolol or labetalol
• When treating women with antihypertensive medication during the postnatal period, use medicines that are taken once daily when possible 
• When possible, avoid using diuretics or angiotensin receptor blockers^[E] to treat hypertension in women in the postnatal period who are breastfeeding or expressing milk 
• Treat women with hypertension in the postnatal period who are not breastfeeding and who are not planning to breastfeed in line with the NICE guideline on hypertension in adults. 

Advice and Follow-up at Transfer to Community Care

Risk of Recurrence of Hypertensive Disorders of Pregnancy

• Advise women with hypertensive disorders of pregnancy that the overall risk of recurrence in future pregnancies is approximately 1 in 5.

Long-term Risk of Cardiovascular Disease

• Advise women who have had a hypertensive disorder of pregnancy that this is associated with an increased risk of hypertension and cardiovascular disease in later life 
• Advise women who have had a hypertensive disorder of pregnancy to discuss how to reduce their risk of cardiovascular disease, including hypertensive disorders, with their GP or specialist. This may include:
  • avoiding smoking, as recommended in the NICE guideline on tobacco: preventing uptake, promoting quitting and treating dependence
  • maintaining a healthy lifestyle, as recommended in the NICE guideline on cardiovascular disease
  • maintaining a healthy weight, as recommended in the NICE guideline on obesity
• In women who have had pre-eclampsia or hypertension with early birth before 34 weeks, consider pre-pregnancy counselling to discuss possible risks of recurrent hypertensive disorders of pregnancy, and how to lower them for any future pregnancies. 

Body Mass Index and Recurrence of Hypertensive Disorders of Pregnancy

• Advise women who have had pre-eclampsia to achieve and keep a body mass index within the healthy range before their next pregnancy (18.5–24.9 kg/m²). See also the NICE guideline on obesity: identification, assessment and management. 

Inter-pregnancy Interval and Recurrence of Hypertensive Disorders of Pregnancy

• Advise women who have had pre-eclampsia that the likelihood of recurrence increases with an inter-pregnancy interval greater than 10 years. 

Long-term Risk of End-stage Kidney Disease

• Tell women with a history of pre-eclampsia who have no proteinuria and no hypertension at the postnatal review (6–8 weeks after the birth) that although the relative risk of end-stage kidney disease is increased, the absolute risk is low and no further follow up is necessary. 

Thrombophilia and the Risk of Pre-eclampsia

• Do not routinely perform screening for thrombophilia in women who have had pre-eclampsia. 

Footnotes

^[A] In 2014, the Medicines and Healthcare products Regulatory Agency (MHRA) issued a drug safety update on ACE inhibitors and angiotensin II receptor antagonists: not for use in pregnancy, which states 'Use in women who are planning pregnancy should be avoided unless absolutely necessary, in which case the potential risks and benefits should be discussed'.

^[B] At the time of publication (June 2019), some brands of nifedipine were specifically contraindicated during pregnancy by the manufacturer in its summary of product characteristics. Refer to the individual summaries of product characteristics for each preparation of nifedipine for further details.

^[C] Although this use is common in UK clinical practice, at the time of publication (June 2019), aspirin did not have a UK marketing authorisation for this indication. Community pharmacies cannot legally sell aspirin as a pharmacy medicine for prevention of pre-eclampsia in pregnancy in England. Aspirin for this indication must be prescribed. The prescriber should see the summary of product characteristics for the manufacturer's advice on use in pregnancy. The prescriber should follow relevant professional guidance, taking full responsibility for the decision. Informed consent should be obtained and documented. See the General Medical Council's Prescribing guidance: prescribing unlicensed medicines for further information.

^[D] The MHRA has issued a warning about the risk of skeletal adverse effects in the neonate following prolonged or repeated use of magnesium sulfate in pregnancy. Maternal administration of magnesium sulfate for longer than 5–7 days in pregnancy has been associated with skeletal adverse effects and hypocalcaemia and hypermagnesemia in neonates. If use of magnesium sulfate in pregnancy is prolonged or repeated, consider monitoring of neonates for abnormal calcium and magnesium levels and skeletal adverse effects.

^[E] In 2009, the MHRA issued a drug safety update on ACE inhibitors and angiotensin II receptor antagonists: recommendations on how to use during breastfeeding, and a subsequent clarification was issued in 2014. This clarification states: 'Although ACE inhibitors and angiotensin II receptor antagonists are generally not recommended for use by breastfeeding mothers, they are not absolutely contraindicated. Healthcare professionals may prescribe these medicines during breastfeeding if they consider that this treatment is essential for the lactating mother. In mothers who are breastfeeding older infants, the use of captopril, enalapril, or quinapril may be considered if an ACE inhibitor is necessary for the mother. Careful follow-up of the infant for possible signs of hypotension is recommended.'