Preeclampsia

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Preeclampsia is a complication of pregnancy in which affected women develop high blood pressure (hypertension); they can also have abnormally high levels of protein in their urine (proteinuria). This condition usually occurs in the last few months of pregnancy and often requires early delivery of the infant. However, this condition can also appear shortly after giving birth (postpartum preeclampsia).

Many women with mild preeclampsia do not feel ill, and the condition is often first detected through blood pressure and urine testing in their doctor's office. In addition to hypertension and proteinuria, signs and symptoms of preeclampsia can include excessive swelling (edema) of the face or hands and a weight gain of more than 3 to 5 pounds in a week due to fluid retention. Affected women may also experience headaches, dizziness, irritability, shortness of breath, a decrease in urination, upper abdominal pain, and nausea or vomiting. Vision changes may develop, including flashing lights or spots, increased sensitivity to light (photophobia), blurry vision, or temporary blindness.

In many cases, symptoms of preeclampsia go away within a few days after the baby is born. In severe cases, however, preeclampsia can damage the mother's organs, such as the heart, liver, and kidneys, and can lead to life-threatening complications. Extremely high blood pressure in the mother can cause bleeding in the brain (hemorrhagic stroke). The effects of high blood pressure on the brain (hypertensive encephalopathy) may also result in seizures. If seizures occur, the condition is considered to have worsened to eclampsia, which can result in coma. About 1 in 200 women with untreated preeclampsia develop eclampsia. Eclampsia can also develop without any obvious signs of preeclampsia.

Between 10 and 20 percent of women with severe preeclampsia develop another potentially life-threatening complication called HELLP syndrome. HELLP stands for hemolysis (premature red blood cell breakdown), elevated liver enzyme levels, and low platelets (cells involved in blood clotting), which are the key features of this condition.

Severe preeclampsia can also affect the fetus, with impairment of blood and oxygen flow leading to growth problems or stillbirth. Infants delivered early due to preeclampsia may have complications associated with prematurity, such as breathing problems caused by underdeveloped lungs.

Women who have had preeclampsia have approximately twice the lifetime risk of heart disease and stroke than do women in the general population. Researchers suggest that preeclampsia, heart disease, and stroke may share common risk factors. Women who have diseases such as obesity, hypertension, heart disease, diabetes, or kidney disease before they become pregnant have an increased risk of developing preeclampsia. Preeclampsia is most likely to occur in a woman's first pregnancy, although it can occur in subsequent pregnancies, particularly in women with other health conditions.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

The specific causes of preeclampsia are not well understood. In pregnancy, blood volume normally increases to support the fetus, and the mother's body must adjust to handle this extra fluid. In some women the body does not react normally to the fluid changes of pregnancy, leading to the signs and symptoms of preeclampsia.

The reasons for these abnormal reactions to the changes of pregnancy vary in different women and may differ depending on the stage of the pregnancy at which the condition develops. Studies suggest that preeclampsia is related to a problem with the placenta, the link between the mother's blood supply and the fetus. If there is an insufficient connection between the placenta and the arteries of the uterus, the placenta does not get enough blood. The placenta responds by releasing a variety of substances, including chemicals that affect the lining of blood vessels (the vascular endothelium). By mechanisms that are unclear, the mother's blood vessels constrict abnormally, causing hypertension. These constricted blood vessels also affect other organs, leading to the other signs and symptoms of preeclampsia. In the kidneys, the constricted blood vessels result in abnormal release of proteins in the urine.

Researchers are studying whether variations in genes involved in fluid balance, the functioning of the vascular endothelium, or placental development affect the risk of developing preeclampsia or its severity. Additional genes with no known function in pregnancy have also been associated with preeclampsia risk.

Many other factors likely also interact with genetic factors and contribute to the risk of developing this complex disorder. These risk factors include a pregnancy with twins or higher multiples, being older than 35 or younger than 20, and preexisting health conditions. Socioeconomic status and ethnicity have also been associated with preeclampsia risk, and nutritional and other environmental factors are thought to affect the likelihood of developing this disorder. The incidence of preeclampsia in the United States has increased by 30 percent in recent years, which has been attributed in part to an increase in older mothers, the increased prevalence of hypertension and obesity, and multiple births resulting from the use of assisted reproductive technologies.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

Many cases of preeclampsia occur in women with no known history of the disorder in their families, and these cases do not seem to be inherited. Some families have a strong family history of the disorder; however, the inheritance pattern is unknown. The tendency to develop preeclampsia can be affected by genetic variations carried by either parent, and genetic variations carried by the fetus may also play a role.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

Preeclampsia is a common condition in all populations, occurring in 5 to 8 percent of pregnancies. It occurs more frequently in women of African or Hispanic descent than it does in women of European descent.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Abnormality of the placenta · Very frequent (99-80%)

An abnormality of the placenta, the organ that connects the developing fetus to the uterine wall to enable nutrient uptake, waste elimination, and gas exchange.

Elevated diastolic blood pressure · Very frequent (99-80%)

Abnormal increase in diastolic blood pressure.

Elevated systolic blood pressure · Very frequent (99-80%)

Abnormal increase in systolic blood pressure.

Hypertension · Very frequent (99-80%)

The presence of chronic increased pressure in the systemic arterial system.

Proteinuria · Very frequent (99-80%)

Increased levels of protein in the urine.

Epigastric pain · Frequent (79-30%)

Pain that is localized to the region of the upper abdomen immediately below the ribs.

Pulmonary edema · Frequent (79-30%)

Fluid accumulation in the lungs.

Renal insufficiency · Frequent (79-30%)

A reduction in the level of performance of the kidneys in areas of function comprising the concentration of urine, removal of wastes, the maintenance of electrolyte balance, homeostasis of blood pressure, and calcium metabolism.

Other findings in the same source

From: Orphanet

Additional reported features include Abdominal pain (Occasional (29-5%)); Abnormality of the hepatic vasculature (Occasional (29-5%)); Abnormality of the kidney (Occasional (29-5%)); Abnormality of the nervous system (Occasional (29-5%)); Abnormality of vision (Occasional (29-5%)); Elevated circulating hepatic transaminase concentration (Occasional (29-5%)); Headache (Occasional (29-5%)); Increased body mass index (Occasional (29-5%)); Intrauterine growth retardation (Occasional (29-5%)); Small for gestational age (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

Which doctor should you see?

The suggested department for discussing Preeclampsia is Obstetrics and Gynaecology, with a obstetrician-gynaecologist as the relevant type of clinician. Obstetrician-gynaecologist; paediatric services for children as appropriate.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• How do age, pregnancy status and reproductive goals affect the assessment?
• Which changes in bleeding, pain or general health need prompt review?
• What are the benefits and risks of the available options in this situation?

Treatment discussions and follow-up

Where the source describes treatments, these are an overview of possible care, not a prescription for an individual. Ask which option applies to the confirmed diagnosis, what benefit is expected, what adverse effects to watch for and how progress will be assessed. Availability, approvals and local practice can differ from the country described in the source.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.