Preeclampsia, or toxemia of pregnancy, is caused by abnormal circulatory conditions and inflammation in the placenta.

Discovery and Symptoms

Preeclampsia is one of the most important conditions that can easily be detected during routine prenatal check-ups, and forms much of the basis for why prenatal check-ups are structured as they are. Most of the time, preeclampsia is discovered during routine examinations in the form of blood pressure changes and proteins in the urine. Other times, the woman seeks medical attention from a doctor or midwife with symptoms such as headaches, epigastric pain, rapidly increasing edema, etc.

The Guide to Obstetrics defines preeclampsia as: “Preeclampsia is defined as new-onset hypertension after 20 weeks of gestation combined with new-onset proteinuria OR other signs of organ dysfunction.” (1)

Diagnostic Criteria

Hypertension:
Systolic BP > 140 mmHg or diastolic BP > 90 mmHg

Proteinuria:
Urine dipstick: at least +1 for protein or protein/creatinine ratio > 0.3 (from a random urine sample)

Other signs of organ dysfunction may include:
Signs of fetal growth restriction, renal impairment (increased creatinine), liver impairment (elevated liver enzymes or epigastric pain), cerebral symptoms: severe headache, visual disturbances. Hematological findings: Low platelets, signs of intravascular coagulation (DIC) or hemolysis.

Women at high risk for preeclampsia are often given a prophylactic dose of acetylsalicylic acid from week 12.

Treatment and Follow-up

Preeclampsia is always treated in a hospital, and the goal is to keep blood pressure below 150/100 mmHg to avoid complications. However, complete normalization of blood pressure is not desirable before delivery, as this can reduce blood flow to the placenta and thus endanger the fetus. The recommended target blood pressure before birth is below 150 mmHg systolic and 80–100 mmHg diastolic. After birth, a lower blood pressure is aimed for, usually <130–140/80–90 mmHg.

Preeclampsia in Chronic Hypertension

For women with previously known hypertension, the same blood pressure limits apply. These women have what is known as chronic hypertension and should be followed and treated with medications compatible with pregnancy, usually under the care of their general practitioner. However, it is important to be aware that these women have an increased risk of developing preeclampsia, and that blood pressure medications can mask a rising pressure. If a pregnant woman with known hypertension develops signs of organ affection, it is considered preeclampsia.

Definitive Treatment

The only definitive treatment for preeclampsia is to remove the cause of the disease – i.e., the placenta. In practice, this means that labor must be induced, or a C-section performed, either if symptoms cannot be controlled, or at 37 weeks of gestation if the condition is stable and treatment is effective, so that the pregnancy can safely be completed as far as possible.