Free family guide · Warning signs and common problems

Preeclampsia

MedlinePlus says gestational high blood pressure and preeclampsia start after 20 weeks, and high blood pressure is often found only at checkups.[1]

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Sources on this page: MedlinePlus; ACOG; NHS; USPSTF; NICHD

This page shares what health organizations say. It is not medical advice. It is general information. Talk to your doctor, midwife or pediatrician about your own situation.

In an emergency, call 911.

When it can happen

ACOG says preeclampsia usually happens after 20 weeks, often in the third trimester, and can also happen in the weeks after birth.[2] The NHS says it can happen in the second half of pregnancy or after birth.[3]

The US Preventive Services Task Force advises blood pressure screening throughout pregnancy.[4] The NHS says checkups look at your blood pressure and the protein in your urine.[5]

Warning signs

MedlinePlus lists these signs of preeclampsia:[1]

  • protein in the urine;[1]
  • swelling of the face and hands;[1]
  • a headache that does not go away;[1]
  • changes in vision;[1]
  • pain in the upper right belly;[1]
  • trouble breathing.[1]

The NHS says to call a doctor or midwife for a severe headache, vision problems or pain just below the ribs.[3] It says sudden vision problems or sudden swelling of the face, hands, legs or feet need checking right away.[6]

ACOG says to call your provider right away for a headache that will not go away together with swelling, vision changes, upper belly or shoulder pain, nausea and vomiting in the second half, sudden weight gain or trouble breathing, especially in the second half of pregnancy or within 6 weeks of birth.[2]

NICHD says a related condition, HELLP syndrome, can happen even without high blood pressure or protein in the urine.[7]

Things linked to higher risk

ACOG says excess weight is linked to high blood pressure and preeclampsia.[8] It says exercise in pregnancy may lower the risk of preeclampsia.[9]

Questions families ask

Can preeclampsia happen after birth?

ACOG says it can happen in the weeks after birth.[2] The NHS also says it can happen after birth.[3]

Is swelling a sign of preeclampsia?

MedlinePlus lists swelling of the face and hands among the signs.[1] The NHS says to mention swelling of the face, hands or feet so your blood pressure can be checked.[3]

Free from UpOnly Learning. Written for families of every faith. No outside ads and no affiliate links. Every fact on this page comes from the sources listed below. How we source and review these pages

Updated 2026-10-24: first published.

Sources

All sources were opened and checked on the date shown.

  1. MedlinePlus (National Library of Medicine). High Blood Pressure in Pregnancy. Checked October 24, 2026.
  2. American College of Obstetricians and Gynecologists. Headaches and Pregnancy. Checked October 24, 2026.
  3. NHS (United Kingdom). 25 weeks pregnant guide. Checked October 24, 2026.
  4. US Preventive Services Task Force. Hypertensive Disorders of Pregnancy: Screening. Checked October 24, 2026.
  5. NHS (United Kingdom). 16 weeks pregnant guide. Checked October 24, 2026.
  6. NHS (United Kingdom). Pregnancy symptoms you need to get help for. Checked October 24, 2026.
  7. Eunice Kennedy Shriver National Institute of Child Health and Human Development (NIH). What are the symptoms of preeclampsia, eclampsia, & HELLP syndrome?. Checked October 24, 2026.
  8. American College of Obstetricians and Gynecologists. Good Health Before Pregnancy: Prepregnancy Care. Checked October 24, 2026.
  9. American College of Obstetricians and Gynecologists. Exercise During Pregnancy. Checked October 24, 2026.