Introduction
High blood pressure during pregnancy is a serious health concern that can affect both the mother and the developing baby. Known medically as hypertensive disorders of pregnancy, these conditions are one of the leading causes of maternal and fetal complications worldwide.
In this guide, we’ll break down:
- The different types of hypertension in pregnancy
- When and how to treat high blood pressure during pregnancy
- Safe medications for mothers and their babies
- Special considerations like preeclampsia, eclampsia, and delivery decisions
This article combines medical detail with plain-language explanations so both healthcare providers and expectant mothers can understand what’s going on and how to respond.
Types of Hypertension in Pregnancy
Hypertensive disorders in pregnancy are classified into four main categories:
1. Chronic Hypertension Definition:
• Blood pressure is already high before pregnancy or diagnosed before 20 weeks of gestation.
Why it matters:
• These women are at a higher risk of developing superimposed preeclampsia later in pregnancy.
N.B: If you had high blood pressure before getting pregnant, it’s called chronic hypertension. Doctors will usually monitor you more closely from the start.
2. Gestational Hypertension
Definition:
• High blood pressure that develops after 20 weeks of pregnancy without protein in the urine or signs of organ damage.
Why it matters:
• Often mild, but can progress to preeclampsia, so careful monitoring is essential
3. Preeclampsia and Eclampsia
Preeclampsia:
• Hypertension after 20 weeks plus proteinuria (≥300 mg/24 hours) or signs of organ dysfunction (liver, kidney, brain, platelets).
Eclampsia:
• Preeclampsia with seizures not explained by another cause.
Why it matters:
• Life-threatening for both mother and baby if untreated.
N.B If you’re pregnant and develop sudden swelling, severe headaches, or vision problems, seek medical attention immediately these can be signs of preeclampsia.
4. Superimposed Preeclampsia
Definition: Chronic hypertension with new-onset proteinuria or worsening blood pressure and organ function after 20 weeks.
Risk: Higher likelihood of severe maternal and fetal complications.
Why Treat Hypertension in Pregnancy?
For the Mother:
- Prevent stroke (especially when BP ≥ 160/110 mmHg)
- Reduce risk of placental abruption (placenta detaching early)
- Prevent progression to eclampsia
For the Baby:
- Maintain good placental blood flow for oxygen and nutrient delivery
- Reduce risk of fetal growth restriction • Avoid premature birth if possible
When to Start Treatment
Blood Pressure Reading Recommended Action
| SBP ≥ 160 or DBP ≥ 110 | Urgent treatment with IV or oral rapid-acting medications |
| Persistent BP > 140/90 | Start oral antihypertensives |
| Mild elevations | Monitor closely, lifestyle advice, possible meds if persisten |
Target Range:
Maintain: 140–150 / 90–100 mmHg
Avoid: SBP < 130 or DBP < 80 mmHg (risk of reduced placental perfusion)
First-Line Medications for Hypertension in Pregnancy
Drug Class Dosage Notes
| Labetalol | β-blocker + α-blocker | PO: 100–400 mg BID– TID; IV: 20 mg over 2 min, repeat q10 min | Preferred IV agent in severe hypertension |
| Methyldopa | Central α2-agonist | PO: 250–500 mg BID–TID | Very safe in pregnancy, slow onset |
| Nifedipine (XL) | Calcium channel blocker | PO: 30–60 mg daily | Avoid sublingual form due to rapid BP drop |
| Hydralazine | Direct vasodilator | IV: 5–10 mg q20–30 min | Used for acute BP control |
Avoid during pregnancy:
- CE inhibitors (enalapril, lisinopril)
- ARBs (losartan, valsartan)
- Direct renin inhibitors (aliskiren)
These can cause fetal kidney damage and birth defects
Special Situations: Severe Hypertension & Preeclampsia/Eclampsia
When blood pressure is very high or preeclampsia is diagnosed:
Magnesium sulfate → Used for seizure prevention in preeclampsia and treatment in eclampsia.
IV antihypertensives → Rapid control to prevent stroke.
Delivery → The only definitive cure for preeclampsia.
• If ≥37 weeks, delivery is usually recommended.
• If earlier, doctors weigh risks of prematurity vs. maternal complications.
Monitoring and Follow-Up
Mother:
- Regular BP checks
- Blood tests: liver enzymes, kidney function, platelets
- Urine protein monitoring
Baby:
- Ultrasound for growth
- Doppler flow studies • Non-stress tests
Lifestyle and Supportive Measures
- Rest, but avoid strict bed rest unless medically indicated.
- Balanced diet with adequate protein and calcium.
- Avoid high-salt processed foods.
- Regular prenatal visits.
N.B You cannot treat pregnancy hypertension with “natural remedies” alone medications are often necessary for safety.
Possible Complications if Untreated
Maternal
stroke, kidney failure, HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelets), seizures.
Fetal
growth restriction, stillbirth, preterm birth.
References
1. https://pubmed.ncbi.nlm.nih.gov/32443079/
2. NICE Guideline NG133. Hypertension in pregnancy: diagnosis and management. 2019.
3. UpToDate. Management of hypertension in pregnancy. 2025 update.
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