Preeclampsia Warning Signs in the Third Trimester
The short answer
Preeclampsia is a serious pregnancy complication characterized by high blood pressure and signs of organ damage, typically occurring after 20 weeks of pregnancy. It affects 5-8% of pregnancies and can progress rapidly. Warning signs include persistent severe headache, vision changes (blurring, spots, light sensitivity), sudden severe swelling (especially face and hands), upper abdominal pain (especially right side), nausea or vomiting in the second half of pregnancy, and sudden weight gain from fluid retention. These symptoms require immediate medical evaluation.
Thousands of parents search for this exact thing. You are not alone.
By Age
What to expect by age
20-28 weeks
Early-onset preeclampsia (before 34 weeks) is less common but tends to be more severe. Risk factors include first pregnancy, previous preeclampsia, chronic hypertension, kidney disease, diabetes, autoimmune conditions, obesity, age over 35 or under 20, IVF pregnancy, and carrying multiples. If you have risk factors, your provider may recommend low-dose aspirin starting at 12-16 weeks. Regular prenatal visits include blood pressure checks and urine screening, which help catch early signs. If diagnosed this early, close monitoring and possible hospitalization may be needed.
28-37 weeks
This is the most common window for preeclampsia to develop. Learn and watch for warning signs between appointments: persistent headache not relieved by acetaminophen, visual disturbances (flashing lights, blurry vision, spots), pain in the upper right abdomen or shoulder, sudden significant swelling of face, hands, or feet, and nausea or vomiting. If your blood pressure at a prenatal visit is elevated (140/90 or higher), additional testing including blood work and urine protein will be ordered. Treatment depends on severity and gestational age, and may include blood pressure medication, magnesium sulfate, and close monitoring.
37+ weeks and postpartum
Late-onset preeclampsia and postpartum preeclampsia (occurring up to 6 weeks after delivery) are important to recognize. The cure for preeclampsia is delivery, and at 37+ weeks, induction is typically recommended. After delivery, continue to watch for preeclampsia symptoms for several weeks. If you develop severe headache, vision changes, difficulty breathing, or upper abdominal pain after going home from the hospital, seek emergency care. Postpartum preeclampsia can develop even in people who had normal blood pressure throughout pregnancy.
What Should You Do?
When to take action
- Mild swelling of feet and ankles at the end of the day, which is common in pregnancy
- Occasional mild headaches that respond to rest and hydration
- Blood pressure readings that remain normal at prenatal visits
- You notice a significant increase in swelling, particularly in your face and hands
- You have a persistent headache that does not respond to acetaminophen, rest, or hydration
- You are gaining weight rapidly (more than 2 pounds in a week) from fluid retention
- You have any risk factors for preeclampsia and want to discuss prevention
- You have a severe headache with vision changes (blurring, spots, flashing lights)
- You have upper right abdominal pain or right shoulder pain, especially with nausea or vomiting
- You have a blood pressure reading of 160/110 or higher at home
- You have sudden severe swelling with difficulty breathing or chest tightness
- You experience decreased fetal movement along with any preeclampsia symptoms
Sources
Related Resources
Trust your instincts. If something feels wrong, reach out to your pediatrician.
Worrying about your baby means you care. That is a good thing.
Related Maternal Concerns
Signs That Labor Is Starting
True labor is characterized by regular contractions that increase in frequency, duration, and intensity over time, and do not stop with rest, hydration, or position changes. Other signs that labor may be approaching include loss of the mucus plug (bloody show), water breaking (rupture of membranes), persistent lower back pain, and a feeling of increased pelvic pressure. First-time parents are generally advised to head to the hospital when contractions are about 5 minutes apart, lasting 1 minute each, for at least 1 hour (the 5-1-1 rule).
Late Postpartum Preeclampsia
Postpartum preeclampsia can develop within 48 hours of delivery or up to 6 weeks after birth, even in people who did not have preeclampsia during pregnancy. It is characterized by high blood pressure and possible organ damage. It is a medical emergency that requires immediate treatment. Knowing the warning signs after delivery is critical.
Syphilis Screening During Pregnancy: Why It Matters
Syphilis screening during pregnancy is critically important because congenital syphilis (transmitted from parent to baby) has increased dramatically in the US, rising over 900% from 2012 to 2022. Untreated syphilis during pregnancy can cause miscarriage, stillbirth, preterm birth, and serious complications in the newborn. The good news is that syphilis is completely treatable with penicillin, and treatment during pregnancy prevents transmission to the baby in almost all cases. All pregnant individuals should be screened, with repeat screening recommended in high-prevalence areas.
Dealing with Abnormal Prenatal Screening Results
An abnormal prenatal screening result can be terrifying, but it is important to understand that screening tests are designed to cast a wide net and have significant false-positive rates. Most people with abnormal screening results go on to have healthy babies after further testing confirms the baby is fine. An abnormal screening is a reason for more information, not a diagnosis.
Pregnancy Over 35 (Advanced Maternal Age)
While pregnancy after 35 carries some increased risks (including chromosomal abnormalities, gestational diabetes, and hypertension), the vast majority of people over 35 have healthy pregnancies and healthy babies. The term "geriatric pregnancy" is outdated and does not reflect reality. With appropriate prenatal care and monitoring, outcomes are excellent.
Amniocentesis Questions and Fears
Amniocentesis is a diagnostic test performed between 15-20 weeks that analyzes amniotic fluid to detect chromosomal conditions and genetic disorders with over 99% accuracy. The risk of pregnancy loss from the procedure is approximately 1 in 500-1,000 when performed by an experienced provider. Understanding the actual risks can help you make an informed decision.