Preeclampsia

DEFINITION

Preeclampsia is a pregnancy complication characterized by high blood pressure and signs of damage to another organ system, often the kidneys. Preeclampsia usually begins after 20 weeks of pregnancy in a woman whose blood pressure had been normal. Even a slight rise in blood pressure may be a sign of preeclampsia.

Left untreated, preeclampsia can lead to serious — even fatal — complications for both you and your baby. If you have preeclampsia, the only cure is delivery of your baby.

If you’re diagnosed with preeclampsia too early in your pregnancy to deliver your baby, you and your doctor face a challenging task. Your baby needs more time to mature, but you need to avoid putting yourself or your baby at risk of serious complications.

CAUSES

The exact cause of preeclampsia is unknown. Experts believe it begins in the placenta — the organ that nourishes the fetus throughout pregnancy. Early in pregnancy, new blood vessels develop and evolve to efficiently send blood to the placenta. In women with preeclampsia, these blood vessels don’t seem to develop properly. They’re narrower than normal blood vessels and react differently to hormonal signaling, which limits the amount of blood that can flow through them.

Causes of this abnormal development may include:

• Insufficient blood flow to the uterus
• Damage to the blood vessels
• A problem with the immune system
• Certain genes

Other high blood pressure disorders during pregnancy

Preeclampsia is classified as one of four high blood pressure disorders that can occur during pregnancy. The other three are:

• Gestational hypertension. Women with gestational hypertension have high blood pressure but no excess protein in their urine or other signs of organ damage. Some women with gestational hypertension eventually develop preeclampsia.
• Chronic hypertension. Chronic hypertension is high blood pressure that was present before pregnancy or that occurs before 20 weeks of pregnancy. But because high blood pressure usually doesn’t have symptoms, it may be hard to determine when it began.
• Chronic hypertension with superimposed preeclampsia.This condition occurs in women who have chronic high blood pressure before pregnancy who then develop worsening high blood pressure and protein in the urine or other health complications during pregnancy.

SYMPTOMS

Preeclampsia sometimes develops without any symptoms. High blood pressure may develop slowly, but more commonly it has a sudden onset. Monitoring your blood pressure is an important part of prenatal care because the first sign of preeclampsia is commonly a rise in blood pressure. Blood pressure that is 140/90 millimeters of mercury (mm Hg) or greater — documented on two occasions, at least four hours apart — is abnormal.

Other signs and symptoms of preeclampsia may include:

• Excess protein in your urine (proteinuria) or additional signs of kidney problems
• Severe headaches
• Changes in vision, including temporary loss of vision, blurred vision or light sensitivity
• Upper abdominal pain, usually under your ribs on the right side
• Nausea or vomiting
• Decreased urine output
• Decreased levels of platelets in your blood (thrombocytopenia)
• Impaired liver function
• Shortness of breath, caused by fluid in your lungs
• Sudden weight gain and swelling (edema) — particularly in your face and hands — often accompanies preeclampsia. But these things also occur in many normal pregnancies, so they’re not considered reliable signs of preeclampsia.

When to see a doctor

Make sure you attend your prenatal visits so that your care provider can monitor your blood pressure. Contact your doctor immediately or go to an emergency room if you have severe headaches, blurred vision, severe pain in your abdomen or severe shortness of breath.

Because headaches, nausea, and aches and pains are common pregnancy complaints, it’s difficult to know when new symptoms are simply part of being pregnant and when they may indicate a serious problem — especially if it’s your first pregnancy. If you’re concerned about your symptoms, contact your doctor.