Executive Summary: Why This Guide is Different
This article provides the most comprehensive, up-to-date, and patient-focused explanation of the NICE guidelines for hypertension in pregnancy (NG133) available online. While official sources like NICE and NHS Wales offer essential clinical protocols, this guide uniquely bridges the gap between medical guidelines and patient understanding. We translate complex recommendations into clear, actionable advice, covering everything from pre-conception planning and risk assessment through to postnatal care. Crucially, we incorporate the latest evidence and practical insights that go beyond the basic guidance, empowering both prospective parents and healthcare professionals with the knowledge to support safer pregnancies.
Key Update for 2026: The most significant recent change in UK practice, endorsed by NICE, is the routine use of placental growth factor (PLGF)-based testing to aid in the rule-out of pre-eclampsia in women with suspected disease between 20 and 35 weeks of pregnancy. This is a major advancement in managing this complex condition.
Understanding Hypertension in Pregnancy: Definitions and Dangers
Hypertensive disorders complicate 8-10% of all pregnancies and remain a leading cause of maternal and fetal complications worldwide. In the UK, the implementation of evidence-based national guidelines has been pivotal in dramatically reducing maternal deaths from pre-eclampsia. However, these conditions continue to contribute significantly to maternal illness, stillbirths, and neonatal admissions.
It is vital to understand the different types of hypertension in pregnancy, as their management and risks vary considerably:
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Chronic Hypertension: High blood pressure that is present before pregnancy or diagnosed before 20 weeks of gestation.
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Gestational Hypertension: New high blood pressure that develops after 20 weeks of pregnancy, without significant proteinuria or other organ dysfunction.
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Pre-eclampsia: A multisystem disorder characterised by new hypertension after 20 weeks with significant proteinuria and/or evidence of maternal organ dysfunction (e.g., liver, kidney, blood, or neurological involvement) or uteroplacental dysfunction (e.g., fetal growth restriction). This is the most serious form and requires the most vigilant monitoring.
The diagnostic threshold for hypertension in pregnancy is a systolic blood pressure of 140 mmHg or higher and/or a diastolic blood pressure of 90 mmHg or higher. Severe hypertension is defined as 160/110 mmHg or higher and is a medical emergency.
For anyone managing hypertension, understanding your readings over time is critical. You can track trends using tools like our blood pressure average calculator, which helps distinguish consistent hypertension from temporary spikes.
Risk Assessment and Prevention: Who Needs Extra Care?
A cornerstone of modern antenatal care is early identification of women at increased risk of developing pre-eclampsia to initiate preventive therapy.
Risk Factors for Pre-eclampsia
| High-Risk Factors (Start Aspirin 150mg daily from 12 weeks) | Moderate-Risk Factors (Start Aspirin 75mg daily if ≥2 factors present) |
|---|---|
| • Hypertensive disease in a previous pregnancy • Chronic kidney disease • Autoimmune disease (e.g., lupus, APS) • Type 1 or Type 2 diabetes • Chronic hypertension |
• First pregnancy • Age 40 or older • Pregnancy interval >10 years • BMI ≥35 at first visit • Family history of pre-eclampsia • Multiple pregnancy (twins, triplets) |
Low-dose aspirin is the recommended preventive treatment. For maximum benefit, it should be started from 12 weeks of gestation and continued daily until the birth of the baby. This simple intervention can reduce the risk of pre-eclampsia by over 20%.
Diagnosis, Monitoring, and Management by Condition
1. Chronic Hypertension: Care Before and During Pregnancy
Women with known hypertension should receive pre-conception counselling. This involves reviewing medication, as drugs like ACE inhibitors (e.g., lisinopril) and angiotensin receptor blockers (ARBs) are contraindicated in pregnancy due to fetal risk and should be switched to safer alternatives like labetalol or nifedipine.
During pregnancy:
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Treatment Threshold: Medication is recommended if blood pressure is persistently at or above 140/90 mmHg, with a treatment target of below 135/85 mmHg.
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Monitoring: Community midwives typically monitor blood pressure and urine weekly.
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Fetal Surveillance: Includes growth scans at 28, 32, and 36 weeks to check for fetal growth restriction.
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Timing of Birth: For women with well-controlled blood pressure (<160/110 mmHg), planned birth is not routinely recommended before 37 weeks. Timing should be a shared decision between the woman and her senior obstetrician from 37 weeks onward.
2. Gestational Hypertension and Pre-eclampsia: Recognition and Response
Any new rise in blood pressure after 20 weeks requires immediate assessment to rule out pre-eclampsia. This involves blood tests (often called “PET bloods“) to check liver enzymes, kidney function, and platelet count, along with urine tests for protein.
Warning Symptoms for Pre-eclampsia (Seek Immediate Medical Advice):
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Severe, persistent headache
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Visual disturbances (blurring, flashing lights)
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Severe pain just below the ribs or in the upper abdomen
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Sudden swelling of the face, hands, or feet
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Vomiting
Management of Gestational Hypertension involves regular monitoring (often twice-weekly BP checks) and starting antihypertensive treatment if BP reaches 140/90 mmHg, with the same target of <135/85 mmHg.
Management of Pre-eclampsia is more intensive and usually involves hospital assessment. The definitive cure for pre-eclampsia is delivery of the baby and placenta. The management challenge is to balance the risks of continuing the pregnancy for the baby’s maturity against the risks to the mother’s health.
A major diagnostic advance is the use of placental growth factor (PLGF) testing. As per the latest NICE guidance, a single PLGF test can help rule out pre-eclampsia for up to two weeks in women presenting with suspected pre-eclampsia between 20 and 35 weeks, potentially avoiding unnecessary hospital admissions and providing reassurance.
3. Managing Severe Hypertension (>160/110 mmHg)
This is an obstetric emergency. Treatment with fast-acting medication (like oral labetalol or nifedipine) must be given promptly in a hospital setting to reduce the risk of maternal stroke. Blood pressure is monitored every 15-30 minutes until it is safely controlled.
Postnatal Care and Long-Term Health
Hypertension does not always resolve immediately after birth. Careful monitoring must continue:
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Monitoring: Blood pressure should be checked daily for the first 2 days after birth, at least once between days 3-5, and as needed thereafter.
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Medication: Methyldopa (if used) should be stopped within 2 days of delivery. Women may need to continue or start antihypertensives postnatally, with a treatment threshold of 150/100 mmHg.
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Breastfeeding: Most common antihypertensives (labetalol, nifedipine) are considered compatible with breastfeeding. A clear plan for ongoing medication and monitoring by the GP or specialist should be in place at discharge.
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Long-Term Follow-up: Women who have had gestational hypertension or pre-eclampsia have a higher lifelong risk of cardiovascular disease. A formal medical review with a GP 6-8 weeks postnatal is essential. This should include a discussion of future pregnancy planning and long-term health advice on diet, exercise, and cardiovascular risk factors.
For managing health in the long term, tools like a reliable home blood pressure monitor become invaluable. Our guide on how to choose the best home blood pressure monitor in the UK can help you make an informed decision for ongoing health management.
FAQ: Your Questions on NICE Hypertension in Pregnancy Guidelines, Answered
What is the difference between NICE CG107 and NG133?
NICE guideline NG133, published in June 2019, is the current, updated guideline that replaced the older CG107 (from August 2010). NG133 incorporates newer evidence on diagnosis, management, and the use of PLGF testing.
Where can I find the NICE hypertension in pregnancy guidelines PDF?
The official PDF of the NG133 guideline, along with easy-read summaries and pathways, is available on the NICE.org.uk website. Searching for “NICE NG133 PDF” will direct you to the correct page for download.
How do the RCOG guidelines compare to NICE?
The Royal College of Obstetricians and Gynaecologists (RCOG) produces complementary guidance, often in the form of detailed Green-top Guidelines on specific topics like the management of severe pre-eclampsia. In the UK, NICE guidelines are considered the overarching national standard for clinical care, while RCOG guidelines provide specialist-level detail that aligns with and supports NICE recommendations.
What is the latest treatment for hypertension in pregnancy?
First-line drug treatment remains labetalol. The latest significant advancement is in diagnostics: the use of PLGF-based testing to rule out pre-eclampsia in women presenting between 20 and 35 weeks, as recommended in the updated NICE guidance. For treatment of severe hypertension, protocols for rapid reduction of blood pressure to prevent stroke have been standardised.
Is there a difference between ACOG and NICE guidelines?
Yes. The American College of Obstetricians and Gynecologists (ACOG) guidelines are designed for the US healthcare context. Key differences include the diagnostic threshold for hypertension (ACOG uses 140/90 mmHg for diagnosis but may intervene at lower levels) and differing protocols for aspirin dose and surveillance. In the UK, the NICE guidelines are the standard of care.
Conclusion: Knowledge, Vigilance, and Partnership
Managing hypertension in pregnancy is a proactive partnership between a woman and her maternity care team. Understanding the NICE NG133 guidelines empowers you to ask the right questions, recognise warning signs, and actively participate in your care plan. From pre-conception aspirin to postnatal follow-up, a clear, evidence-based pathway exists to ensure the best possible outcomes for both mother and baby.
Always consult your midwife, obstetrician, or GP for personal medical advice. This guide is intended for informational purposes to support those informed discussions.
Disclaimer: This article is for informational purposes and does not constitute medical advice. Always follow the guidance of your qualified healthcare professional.