biology

Hypertensive disease of pregnancy

Hypertensive disease of pregnancy 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 Hypertensive disease of pregnancy rather than just read about it. In short: Hypertensive disease of pregnancy, also known as maternal hypertensive disorder, is a group of high blood pressure disorders that include preeclampsia, preeclampsia superimposed on chronic hypertension, gestational hypertension, and chronic hypertension. Maternal hypertensive disorders occurred in about 20.7 million women in 2013.

Key takeaways

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

Reference excerpt

Hypertensive disease of pregnancy, also known as maternal hypertensive disorder, is a group of high blood pressure disorders that include preeclampsia, preeclampsia superimposed on chronic hypertension, gestational hypertension, and chronic hypertension. Maternal hypertensive disorders occurred in about 20.7 million women in 2013. About 10% of pregnancies globally are complicated by hypertensive diseases. In the United States, hypertensive disease of pregnancy affects about 8% to 13% of pregnancies. Rates have increased in the developing world. They resulted in 29,000 deaths in 2013, down from 37,000 deaths in 1990. They are one of the three major causes of death in pregnancy (16%) along with post partum bleeding (13%) and puerperal infections (2%). Hypertensive disorders during pregnancy, such as gestational hypertension, preeclampsia, and eclampsia, are a major contributor to maternal and fetal illness and death on a worldwide scale. Around 5-10% of pregnancies are affected by these conditions, with preeclampsia being responsible for up to 14% of maternal deaths globally. The effects of HDP are significant, but there is still a limited understanding of its root causes. Studies show an interconnection of genetic, immunological, and environmental elements. Accurately pinpointing particular risk factors has stifled researchers because of the varied nature of Hypertensive disorders of pregnancy. All types of HDP can be caused by a variety of factors, as mentioned above, and can occur in irregular manners.

Signs and symptoms Although many pregnant women with high blood pressure have healthy babies without serious problems, high blood pressure can be dangerous for both the mother and baby. Women with pre-existing, or chronic, high blood pressure are more likely to have certain complications during pregnancy than those with normal blood pressure. However, some women develop high blood pressure while they are pregnant (often called gestational hypertension). Chronic poorly-controlled high blood pressure before and during pregnancy puts a pregnant woman and her baby at risk for problems. It is associated with an increased risk for maternal complications, such as pre-eclampsia, placental abruption (when the placenta separates from the wall of the uterus), and gestational diabetes. These women also face a higher risk for poor birth outcomes such as pre-term delivery, having an infant small for his/her gestational age, and infant death.

Risk factors Some women have a greater risk of developing hypertension during pregnancy. These are:

Women with chronic hypertension (high blood pressure before becoming pregnant). Women who developed high blood pressure or preeclampsia during a previous pregnancy, especially if these conditions occurred early in the pregnancy. Women who are obese before pregnancy. Pregnant women under the age of 15 or over the age of 30. Women who are pregnant with more than one baby. Women with diabetes, kidney disease, rheumatoid arthritis, lupus, or scleroderma. Woman who use artificial reproductive technologies

Diagnosis There is no single test to predict or diagnose preeclampsia. Key signs are increased blood pressure and protein in the urine (proteinuria). Other symptoms that seem to occur with preeclampsia include persistent headaches, blurred vision or sensitivity to light, and abdominal pain. Other disorders can cause all of these sensations; they can also occur in healthy pregnancies. Regular visits are scheduled to track blood pressure and protein levels in urine, to order and analyze blood tests that detect signs of preeclampsia, and to monitor fetal development more closely.

Classification A classification of hypertensive disorders of pregnancy uses 4 categories as recommended by the U.S. National High Blood Pressure Education Program Working Group on High Blood Pressure in Pregnancy:

Chronic hypertension; Preeclampsia-eclampsia; Preeclampsia superimposed on chronic hypertension; Gestational hypertension (transient hypertension of pregnancy or chronic hypertension identified in the latter half of pregnancy). This terminology is preferred over the older but widely used term pregnancy-induced hypertension (PIH) because it is more precise. The newer terminology reflects simply relation of pregnancy with either the onset or first detection of hypertension; the question of causation, while pathogenetically interesting, is not the important point for most health care purposes. This classification treats HELLP syndrome as a type of preeclampsia rather than a parallel entity.

Chronic hypertension Chronic hypertension is a type of high blood pressure in a pregnant woman that is pre-existing before conception, diagnosed early in pregnancy, or persists significantly after the end of pregnancy. It affects about 5% of all pregnancies and can be a primary disorder of essential hypertension or secondary to another condition; it is not caused by pregnancy itself. The diagnostic criteria for chronic hypertension are typically considered to be at least two separate blood pressure readings taken at least four hours apart with systolic blood pressure ≥ 140mmHg, diastolic blood pressure ≥90 mmHg, or both, identified before pregnancy, before 20 weeks of gestation, or persisting at least 12 weeks after giving birth. However, there is some controversy over the utility of adopting lower thresholds for the diagnosis of chronic hypertension, which is more consistent with recent recommendations from the American College of Cardiology and the American Heart Association for the diagnosis of hypertension in adults. Chronic hypertension in pregnancy is now considered mild if blood pressures do not exceed 159 mmHg systolic and 109 mmHg diastolic and severe if pressures are ≥ 160 mmHg systolic or 110 mmHg diastolic, although controversy also exists as to the most appropriate cutoffs for this definition. Because chronic hypertension can progress to more severe forms of disease, it is important to accurately diagnose the condition early, ideally before pregnancy, and initiate management to control parental blood pressure. This is often difficult, as many reproductive individuals may not regularly visit the doctor and, when pregnant, may initially present for prenatal care in the second trimester.

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Worked examples

Example 1 — a first encounter with Hypertensive disease of pregnancy

Start with the simplest possible case. Write down what Hypertensive disease of pregnancy 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 Hypertensive disease of pregnancy 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 Hypertensive disease of pregnancy 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 Hypertensive disease of pregnancy

In research: Hypertensive disease of pregnancy 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 Hypertensive disease of pregnancy 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: Hypertensive disease of pregnancy is common in secondary-school and first-year university syllabi. It links to neighbouring topics Health issues in pregnancy, Hypertension, Women's health, so understanding it makes those chapters shorter.
In everyday life: Look for Hypertensive disease of pregnancy 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 Hypertensive disease of pregnancy in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Hypertensive disease of pregnancy means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Hypertensive disease of pregnancy out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Hypertensive disease of pregnancy in simple terms?

Why does Hypertensive disease of pregnancy 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 Hypertensive disease of pregnancy?

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 Hypertensive disease of pregnancy.