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Pre-eclampsia

Pre-eclampsia is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Pre-eclampsia rather than just read about it. In short: Pre-eclampsia (also spelled preeclampsia in US English) is a multi-system disorder specific to pregnancy, characterized by the new onset of high blood pressure and often a significant amount of protein in the urine (proteinuria) or by the new onset of high blood pressure along with significant end-organ damage, with or without the proteinuria. When it arises, the condition begins after 20 weeks of pregnancy.

Pre-eclampsia — main illustration
Pre-eclampsia — illustration

Key takeaways

  • Pre-eclampsia belongs to biology; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Pre-eclampsia to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Pre-eclampsia from memory before moving on to harder problems.

Reference excerpt

Pre-eclampsia (also spelled preeclampsia in US English) is a multi-system disorder specific to pregnancy, characterized by the new onset of high blood pressure and often a significant amount of protein in the urine (proteinuria) or by the new onset of high blood pressure along with significant end-organ damage, with or without the proteinuria. When it arises, the condition begins after 20 weeks of pregnancy. In severe cases of the disease there may be red blood cell breakdown, a low blood platelet count, impaired liver function, kidney dysfunction, swelling, shortness of breath due to fluid in the lungs, or visual disturbances. Pre-eclampsia increases the risk of undesirable as well as lethal outcomes for both the mother and the fetus including preterm labor. If left untreated, it may result in seizures at which point it is known as eclampsia. Risk factors for pre-eclampsia include obesity, prior hypertension, older age, and diabetes mellitus. It is also more frequent in a woman's first pregnancy and if she is carrying twins. The underlying mechanisms are complex and involve abnormal formation of blood vessels in the placenta amongst other factors. Most cases are diagnosed before delivery, and may be categorized depending on the gestational week at delivery. Commonly, pre-eclampsia continues into the period after delivery, then known as postpartum pre-eclampsia. Rarely, pre-eclampsia may begin in the period after delivery. While historically both high blood pressure and protein in the urine were required to make the diagnosis, some definitions also include those with hypertension and any associated organ dysfunction. Blood pressure is defined as high when it is greater than 140 mmHg systolic or 90 mmHg diastolic at two separate times, more than four hours apart in a woman after twenty weeks of pregnancy. Pre-eclampsia is routinely screened during prenatal care. Recommendations for prevention include: aspirin in those at high risk, calcium supplementation in areas with low intake, and treatment of prior hypertension with medications. In those with pre-eclampsia, delivery of the baby and placenta is an effective treatment but full recovery can take days or weeks. The point at which delivery becomes recommended depends on how severe the pre-eclampsia is and how far along in pregnancy a woman is. Blood pressure medication, such as labetalol and methyldopa, may be used to improve the mother's condition before delivery. Magnesium sulfate may be used to prevent eclampsia in those with severe disease. Bed rest and dietary salt restriction are not useful for either treatment or prevention. Pre-eclampsia affects 2–8% of pregnancies worldwide. Hypertensive disorders of pregnancy (which include pre-eclampsia) are one of the most common causes of death due to pregnancy. They resulted in 46,900 deaths in 2015. Pre-eclampsia usually occurs after 32 weeks; however, if it occurs earlier it is associated with worse outcomes. Women who have had pre-eclampsia are at increased risk of high blood pressure, heart disease, and stroke later in life. Further, those with pre-eclampsia may have a lower risk of breast cancer.

Etymology The word "eclampsia" is from the Greek term ἔκλᾰμψῐς (éklămpsĭs, "sudden development, violent onset", literally "brightness"). The first known description of the condition was by Hippocrates in the 5th century BC. An outdated medical term for pre-eclampsia is toxemia of pregnancy, a term that originated in the mistaken belief that the condition was caused by toxins.

Signs and symptoms

Edema (especially in the hands and face) was originally considered an important sign for a diagnosis of pre-eclampsia. However, because edema is a common occurrence in pregnancy, its utility as a distinguishing factor in pre-eclampsia is not high. Pitting edema (unusual swelling, particularly of the hands, feet, or face, notable by leaving an indentation when pressed on) can be significant and should be reported to a healthcare provider. Further, a symptom such as epigastric pain may be misinterpreted as heartburn. Standard features of pre-eclampsia, which are screened for during prenatal visits, include elevated blood pressure and excess protein in the urine. Additionally, some women may develop severe headaches as a sign of pre-eclampsia. In general, none of the signs of pre-eclampsia are specific, and even convulsions in pregnancy are more likely to have causes other than eclampsia in modern practice. Diagnosis depends on finding a coincidence of several pre-eclamptic features, the final proof being their regression within the days and weeks after delivery.

Causes The cause of preeclampsia is not fully understood. It is likely related to factors such as:

… excerpt ends here. Continue reading the full article.

Illustrations

Pre-eclampsia illustration
Pre-eclampsia: Symptoms of preeclampsia
Symptoms of preeclampsia
Pre-eclampsia illustration

Worked examples

Example 1 — a first encounter with Pre-eclampsia

Start with the simplest possible case. Write down what Pre-eclampsia claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Pre-eclampsia before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Pre-eclampsia ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Pre-eclampsia

In research
Pre-eclampsia appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Pre-eclampsia in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Pre-eclampsia is common in secondary-school and first-year university syllabi. It links to neighbouring topics Health issues in pregnancy, Hypertension, Medical emergencies, so understanding it makes those chapters shorter.
In everyday life
Look for Pre-eclampsia outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Pre-eclampsia in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Pre-eclampsia means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Pre-eclampsia out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Pre-eclampsia in simple terms?

Pre-eclampsia (also spelled preeclampsia in US English) is a multi-system disorder specific to pregnancy, characterized by the new onset of high blood pressure and often a significant amount of protein in the urine (proteinuria) or by the new onset of high blood pressure along with significant end…

Why does Pre-eclampsia matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Pre-eclampsia?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Pre-eclampsia.

Tags

  • Health issues in pregnancy
  • Hypertension
  • Medical emergencies
  • Rare diseases
  • Women's health

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