Protocol · WHO maternal health
Hypertension in pregnancy and pre-eclampsia
Pre-eclampsia often causes no symptoms until it is severe, and it can get worse fast. Measuring blood pressure at every antenatal and postnatal contact finds it early. Severe pre-eclampsia and eclampsia need magnesium sulfate, control of very high blood pressure and urgent transfer to a facility that can deliver the baby.
- Based on WHO maternal health
- For midwives, nurses, clinical officers and doctors
- Reviewed October 2026
1Who / when
- Any pregnant woman with BP 140/90 or higher, and any woman with a convulsion in pregnancy or up to 6 weeks after birth.
- Measure BP at every antenatal and postnatal contact. Pre-eclampsia may have no symptoms; swollen feet alone are not a reliable sign.
- Treat any convulsion in pregnancy as eclampsia until proven otherwise; some women with eclampsia have normal BP.
2Red flags: refer now
- Convulsion, or unconscious.
- BP 160/110 or higher.
- Severe or worsening headache, blurred vision.
- Pain in the upper abdomen (epigastric or right upper), nausea or vomiting.
- Breathlessness (fluid on the lungs), passing little urine.
- Brisk reflexes or clonus.
Act nowAny one of these with raised BP after 20 weeks is severe pre-eclampsia: give magnesium sulfate, lower severe BP and transfer urgently. Never leave the woman alone.
3Assess
- Measure BP sitting, rested; repeat. Two readings of 140/90 or more four hours apart confirm hypertension.
- Before 20 weeks: likely chronic hypertension. After 20 weeks: gestational hypertension or pre-eclampsia.
- Urine protein on a clean-catch midstream sample: 2+ or more on dipstick is significant (UTI, severe anaemia and blood can give false positives).
- Ask about headache, vision, abdominal pain, breathing, urine output, fetal movements. Check reflexes, chest, fetal heart.
- If a laboratory is available: platelets, liver enzymes, creatinine. A bedside clotting test if severe.
4Classify
| Findings (after 20 weeks unless stated) | Classify as | Action |
|---|---|---|
| Convulsions with BP 140/90 or more | Eclampsia | Magnesium sulfate, control BP, urgent transfer; birth within 12 hours of the fit |
| BP 160/110 or more or any red flag symptom, with proteinuria 2+ | Severe pre-eclampsia | Magnesium sulfate, control BP, urgent transfer for birth |
| BP 140 to 159 / 90 to 109, proteinuria 2+, no severe features | Pre-eclampsia (mild) | Refer for assessment; review twice weekly; induction at 37 weeks |
| BP 140 to 159 / 90 to 109, no proteinuria, no features | Gestational hypertension | BP, urine and fetus weekly; induce at term if no labour |
| BP 140/90 or more before 20 weeks | Chronic hypertension | Treat (see below); watch for superimposed pre-eclampsia |
5Treat
Magnesium sulfate: the anticonvulsant of choice
| Regimen | Loading dose | Maintenance (24 h after birth or last fit, whichever is later) |
|---|---|---|
| Intramuscular | 4 g of 20% IV over 5 minutes, then 10 g of 50% deep IM: 5 g in each buttock with 1 mL 2% lidocaine | 5 g of 50% deep IM every 4 hours, alternate buttocks |
| Intravenous | 4 g IV | 1 g per hour by infusion (pump if available) |
Before each repeat dose check: breathing 16 per minute or more, knee reflexes present, urine 30 mL per hour or more over 4 hours. If not, delay or stop. Respiratory arrest: ventilate and give calcium gluconate 1 g (10 mL of 10%) IV slowly over 3 minutes.
Lower BP of 160/110 or more (choose by experience, cost and availability)
- Nifedipine immediate-release 5 to 10 mg by mouth, repeat after 30 minutes if needed (maximum 30 mg in the acute phase).
- Labetalol 200 mg by mouth, repeat after 1 hour (not with asthma or heart failure); or hydralazine or labetalol IV where trained.
- Methyldopa 750 mg by mouth, repeat after 3 hours (maximum 3 g in 24 hours).
- Keep BP above the lower limit of normal: do not drop it too far.
Non-severe hypertension (140 to 159 / 90 to 109): WHO 2020 says offer treatment where there is good antenatal follow-up; oral methyldopa or a beta-blocker are reasonable choices. Never ACE inhibitors, ARBs or diuretics in pregnancy. No ergometrine for women with high BP.
6Follow-up
- Gestational hypertension: BP, urine protein and fetal well-being every week.
- Mild pre-eclampsia managed as an outpatient: twice a week, with danger-sign advice.
- After birth: continue antihypertensives if she was on them; treat severe postpartum hypertension. BP often peaks towards the end of the first week, after discharge, so check it at every postnatal contact.
7Counsel
- Prevention: low-dose aspirin 75 mg daily, started before 20 weeks (ideally from 12 weeks), for women at high risk: previous pre-eclampsia, diabetes, chronic hypertension, kidney or autoimmune disease, twins.
- Calcium 1.5 to 2.0 g a day where diets are low in calcium.
- Bed rest, salt restriction, vitamins C, D or E and diuretics do not prevent pre-eclampsia.
- Know the danger signs; plan to give birth in a facility; keep transport ready.
Your blood pressure is high, which can be dangerous for you and the baby. If you get a bad headache, blurred vision, pain high in your belly, trouble breathing or a fit, come straight away, day or night.
8When to refer
- Urgently, after the first doses: eclampsia, severe pre-eclampsia, BP 160/110 or more.
- Pre-eclampsia of any severity, for assessment and a plan for birth.
- Gestational hypertension that is worsening, or with poor fetal growth or reduced movements.
- Postpartum BP 160/110 or more, or new symptoms after birth.
- Send the woman with a health worker, the referral note and the doses given.
9Sources
- World Health Organization. WHO recommendations for prevention and treatment of pre-eclampsia and eclampsia. 2011 (ISBN 9789241548335).
- World Health Organization. WHO recommendations on drug treatment for non-severe hypertension in pregnancy. 2020 (ISBN 9789240008793).
- World Health Organization. Managing complications in pregnancy and childbirth: a guide for midwives and doctors, 2nd edition. 2017 (ISBN 9789241565493). Used for classification, magnesium sulfate and antihypertensive doses.
- World Health Organization. WHO recommendations on antenatal care for a positive pregnancy experience. 2016.
Adapted from WHO guidance; not endorsed by WHO. This page paraphrases and adapts the WHO publications listed under Sources, which are licensed CC BY-NC-SA 3.0 IGO; the adapted text is shared under the same licence for non-commercial education. Reasoning GP is not affiliated with WHO or any other organisation named here. Use it alongside your national guidelines, essential medicines list and formulary, and your clinical judgement. Doses are given only where they come from a WHO source; otherwise follow your national guideline or formulary.