Pre-eclampsia and high blood pressure in pregnancy
Pre-eclampsia causes high blood pressure, usually with protein in the urine, after 20 weeks of pregnancy. It affects about 2 to 8 in 100 pregnancies and can become serious for mother and baby if untreated. It often has no symptoms at first, which is why your blood pressure is checked at every visit. A severe headache, vision problems, pain under the ribs or sudden swelling need urgent care.
Key facts
| High blood pressure | 140/90 or above |
|---|---|
| Severe | 160/110 or above |
| When | After 20 weeks, and up to 6 weeks after birth |
| Prevention if high risk | Low-dose aspirin from 12 weeks, if prescribed |
| Cure | Birth of the baby and placenta |
What is pre-eclampsia?
It's a problem with the placenta that affects blood vessels throughout the body. Blood pressure rises, the kidneys leak protein, and the liver, brain and baby's growth can be affected.
Symptoms
- Often none at first
- Severe headache that doesn't go away with simple painkillers
- Blurred vision, flashing lights or spots
- Pain just below the ribs, especially on the right
- Vomiting in the second half of pregnancy
- Sudden swelling of the face, hands or feet
- Feeling very unwell
Call your maternity unit or emergency number straight away if you have any of these after 20 weeks.
Who's at higher risk?
- Pre-eclampsia or high blood pressure in a previous pregnancy
- Long-term high blood pressure, kidney disease, diabetes, lupus
- First pregnancy, age 40 or over, BMI of 35 or more
- Twins or more
- More than 10 years since your last pregnancy, or a family history
Can it be prevented?
If you're at higher risk, your doctor may prescribe low-dose aspirin daily from 12 weeks until birth. Don't start aspirin without advice. Where diets are low in calcium, the World Health Organization recommends calcium supplements in pregnancy.
Checking your blood pressure
If you use a home monitor, sit quietly for 5 minutes, rest your arm at heart level, and take two readings. Bring your readings to appointments.
Treatment
Treatment includes regular monitoring, blood pressure medicines that are safe in pregnancy, and sometimes a hospital stay. Magnesium sulphate may be given to prevent seizures in severe cases. Because the cure is birth, your baby may be delivered early, often by 37 weeks.
After birth
Pre-eclampsia can start or continue after birth, so keep watching for symptoms for 6 weeks. It raises your long-term risk of high blood pressure and heart disease, so have your blood pressure checked every year.
Frequently asked questions
Does salt cause pre-eclampsia?
Will my baby be okay?
Will I get it again?
Sources
- NICE NG133: Hypertension in pregnancy
- WHO: Recommendations for prevention and treatment of pre-eclampsia and eclampsia
- ACOG Practice Bulletin 222
- Preeclampsia Foundation
General information, not medical advice. Medical disclaimer · How we review content
Keep reading
Pregnancy warning signs: when to go to hospital
The pregnancy symptoms that need urgent care: bleeding, reduced movements, severe headache, fluid leaking, fever and more. Know when to call.
Third trimester · 7 minThird trimester guide: weeks 28 to birth
The third trimester week by week: your baby turning head down, common symptoms and relief, appointments, getting ready for birth, and warning signs.
Health · 5 minHow much weight should you gain in pregnancy?
Healthy pregnancy weight gain by BMI, where the weight goes, and how to stay on track without dieting.