Obstetrical bleeding

Key takeaways

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

Reference excerpt

Obstetrical bleeding is bleeding in pregnancy that occurs before, during, or after childbirth. Bleeding before childbirth is that which occurs after 24 weeks of pregnancy. Bleeding may be vaginal or, less commonly, into the abdominal cavity. Bleeding that occurs before 24 weeks is known as early pregnancy bleeding. Causes of bleeding before and during childbirth include cervicitis, placenta previa, placental abruption and uterine rupture. Causes of bleeding after childbirth include poor contraction of the uterus, retained products of conception, and bleeding disorders. About 8.7 million cases of severe maternal bleeding occurred in 2015 resulting in 83,000 deaths. Between 2003 and 2009, bleeding accounted for 27% of maternal deaths globally.

Later pregnancy

Antepartum bleeding (APH), also prepartum hemorrhage, is bleeding during pregnancy from the 24th week (sometimes defined as from the 20th week) gestational age up to the birth of the baby. The primary consideration is the presence of a placenta previa, which is a low-lying placenta at or very near to the internal cervical os. This condition occurs in roughly 4 out of 1000 pregnancies and usually needs to be resolved by delivering the baby via cesarean section. Also, a placental abruption (in which there is premature separation of the placenta) can lead to obstetrical hemorrhage, sometimes concealed. This pathology is of important consideration after maternal trauma, such as a motor vehicle accident or fall. Other considerations to include when assessing antepartum bleeding are: sterile vaginal exams that are performed to assess dilation of the patient when the 40th week is approaching. Cervical insufficiency is defined as a midtrimester (14th-26th week) dilation of the cervix, which may need medical intervention to assist in keeping the pregnancy sustainable.

During labor Besides placenta previa and placental abruption, uterine rupture can occur, which is a very serious condition leading to internal or external bleeding. Bleeding from the fetus is rare, but may occur with two conditions called vasa previa and velamentous umbilical cord insertion, where the fetal blood vessels lie near the placental insertion site unprotected by Wharton's jelly of the cord. Occasionally this condition can be diagnosed by ultrasound. There are also tests to differentiate maternal blood from fetal blood, which can help in determining the source of the bleed.

After delivery

Abnormal bleeding after delivery, or postpartum hemorrhage, is the loss of greater than 500 ml of blood following vaginal delivery, or 1000 ml of blood following cesarean section. Other definitions of excessive postpartum bleeding are hemodynamic instability, drop of hemoglobin of more than 10%, or requiring blood transfusion. In the literature, primary postpartum hemorrhage is defined as uncontrolled bleeding that occurs in the first 24 hours after delivery, while secondary hemorrhage occurs between 24 hours and six weeks.

Risk factors In rare cases, inherited bleeding disorders, like hemophilia, von Willebrand disease (vWD), or factor IX or XI deficiency, may cause severe postpartum hemorrhage, with an increased risk of death, particularly in the postpartum period. The risk of postpartum hemorrhage in patients with vWD and carriers of hemophilia is 18.5% and 22%, respectively. This pathology occurs due to the normal physiological drop in maternal clotting factors after delivery, which greatly increases the risk of secondary postpartum hemorrhage. Another bleeding risk factor is thrombocytopenia, or decreased platelet levels, which is the most common hematological change associated with pregnancy-induced hypertension. If platelet counts drop less than 100,000 per microliter, the patient will be at a severe risk for inability to clot during and after delivery.

Medical tests If a small amount of bleeding is seen in early pregnancy, a physician may request:

A quantitative human chorionic gonadotropin (hCG) blood test to confirm the pregnancy or assist in diagnosing a potential miscarriage Transvaginal pelvic ultrasonography to confirm that the pregnancy is not outside of the uterus Blood type and Rh test to rule out hemolytic disease of the newborn For bleeding seen in later pregnancy tests may include:

Complete blood count (CBC) and blood type and screen Ultrasound to determine placental location Kleihauer-Betke (KB) test, especially if there was maternal trauma

Unrelated bleeding Pregnant patients may have bleeding from the reproductive tract due to trauma, including sexual trauma, neoplasm, most commonly cervical cancer, and hematologic disorders. Molar pregnancy (also called hydatiform mole) is a type of pregnancy where the sperm and the egg have joined within the uterus, but the result is a cyst resembling a grape-like cluster rather than an embryo. Bleeding can be an early sign of this tumor developing.

See also Gynecologic bleeding Non-pneumatic anti-shock garment

References

External links

Worked examples

Example 1 — a first encounter with Obstetrical bleeding

Start with the simplest possible case. Write down what Obstetrical bleeding claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Obstetrical bleeding 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 Obstetrical bleeding 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 Obstetrical bleeding

In research: Obstetrical bleeding appears in science 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 Obstetrical bleeding 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: Obstetrical bleeding is common in secondary-school and first-year university syllabi. It links to neighbouring topics Complications of labour and delivery, Health issues in pregnancy, Medical emergencies, so understanding it makes those chapters shorter.
In everyday life: Look for Obstetrical bleeding 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.

How to study Obstetrical bleeding in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Obstetrical bleeding 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 Obstetrical bleeding out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Obstetrical bleeding in simple terms?

Obstetrical bleeding is bleeding in pregnancy that occurs before, during, or after childbirth. Bleeding before childbirth is that which occurs after 24 weeks of pregnancy.

Why does Obstetrical bleeding matter?

Because it connects several science 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 Obstetrical bleeding?

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 Obstetrical bleeding.