Preeclampsia risk factors: who is more likely to get it, warning signs and aspirin

What preeclampsia is

Preeclampsia is a sudden increase in blood pressure after the 20th week of pregnancy, usually in the last trimester. It often includes signs of damage to organs such as the liver or kidneys, for example protein in the urine and very high blood pressure. It can be serious or even life-threatening for both you and your baby (MedlinePlus). It can include blood pressure at or above 140/90 mmHg, and it is a leading cause of preterm birth (before 37 weeks of pregnancy) (NICHD).

If preeclampsia affects brain function and causes seizures or coma, it is called eclampsia. HELLP syndrome is a serious complication in which a person with preeclampsia or eclampsia has damage to the liver and blood cells (NICHD). Preeclampsia can also start after delivery, usually between 48 hours and 6 weeks after the birth, even if blood pressure was normal during pregnancy (NICHD).

Preeclampsia is a complication in approximately 4% of pregnancies in the US (USPSTF 2021).

Risk factors

Preeclampsia occurs mainly in first pregnancies. A woman who had preeclampsia in a previous pregnancy is seven times more likely to develop it in a later pregnancy (NICHD). NICHD lists these other factors that can increase risk (NICHD):

• chronic high blood pressure or kidney disease before pregnancy
• high blood pressure or preeclampsia in an earlier pregnancy
• obesity; women with overweight or obesity are also more likely to have preeclampsia in more than one pregnancy
• age older than 40
• being pregnant with more than one fetus (twins or more)
• African American ethnicity
• a family history of preeclampsia

Preeclampsia is also more common in people with a history of certain health conditions, such as migraines, diabetes, rheumatoid arthritis, lupus, scleroderma, urinary tract infections, gum disease, polycystic ovary syndrome, multiple sclerosis, gestational diabetes and sickle cell disease. It is also more common in pregnancies from egg donation, donor insemination or in vitro fertilization (IVF) (NICHD).

MedlinePlus gives a similar list for high blood pressure in pregnancy, and adds being under age 20 as well as over age 40 (MedlinePlus).

How USPSTF sorts the risk factors

The USPSTF groups risk factors found from your medical history into high and moderate risk (USPSTF 2021).

USPSTF notes that the higher risk in Black persons comes from social, environmental and historical inequities in health care and resources, not from biology (USPSTF 2021). The preeclampsia risk and aspirin check walks you through this table.

Aspirin advice

The USPSTF recommends low-dose aspirin (81 mg a day) after 12 weeks of pregnancy for people at high risk of preeclampsia (grade B) (USPSTF 2021). If you are pregnant or thinking about getting pregnant, talk with your health care provider about your risk and ways to lower it (NICHD). Do not start aspirin in pregnancy without talking to your provider first.

Warning signs to report right away

High blood pressure usually has no symptoms; it is found when your blood pressure is measured (MedlinePlus). Your provider checks your blood pressure and urine at each prenatal visit, and a reading of 140/90 or higher, especially after week 20, will likely lead to more tests (MedlinePlus). See the blood pressure in pregnancy check.

Preeclampsia can cause symptoms such as (MedlinePlus):

• swelling in your face and hands (swollen feet alone are common in pregnancy and may not be a sign of a problem)
• a headache that does not go away
• vision problems, such as blurred vision or seeing spots
• pain in your upper right belly
• trouble breathing

NICHD lists seizures, severe headache, vision problems such as temporary blindness, belly pain especially in the upper right area, nausea and vomiting, and passing less urine as cause for immediate concern (NICHD). If you have any of these during pregnancy or in the weeks after birth, call your provider or get emergency care now. Eclampsia is a medical emergency (NICHD).

Why it matters

High blood pressure in pregnancy can lead to the placenta separating from the uterus, poor growth of the baby, preterm birth, low birth weight, damage to your kidneys, liver, brain and other organs, and a higher risk of heart disease for you later (MedlinePlus). Delivering the baby can help resolve preeclampsia, and treatment depends on how severe it is and how far along the pregnancy is (NICHD). Symptoms usually go away within 6 weeks of delivery (NICHD).

Diabetes and gestational diabetes are on the risk list above; see gestational diabetes risk factors and the high blood pressure risk factors.

Common questions

Can I get preeclampsia in my first pregnancy with no other risk factors?

Yes. Preeclampsia occurs mainly in first pregnancies (NICHD), and USPSTF counts a first pregnancy as a moderate risk factor (USPSTF 2021). Keep going to your prenatal visits so your blood pressure is checked.

If I had preeclampsia before, will I get it again?

Not always, but the chance is higher: NICHD says seven times more likely in a later pregnancy (NICHD). USPSTF counts it as a high-risk factor for aspirin (USPSTF 2021).

Can preeclampsia start after the baby is born?

Yes. Postpartum preeclampsia usually develops between 48 hours and 6 weeks after delivery, even without high blood pressure during pregnancy (NICHD).