A 38-year-old woman, gravida 2, para 1, at 35 weeks' gestation comes to the emergency department because of an episode of vaginal bleeding that morning. The bleeding has subsided. She has had no prenatal care. Her previous child was delivered with a caesarean section because of a breech presentation. Her temperature is 37.1°C (98.8°F), pulse is 88/min, respirations are 14/min, and blood pressure is 125/85 mm Hg. The abdomen is nontender and the size of the uterus is consistent with a 35-week gestation. No contractions are felt. The fetal heart rate is 145/min. Her hemoglobin concentration is 12 g/dL, leukocyte count is 13,000/mm3, and platelet count is 350,000/mm3. Transvaginal ultrasound shows that the placenta covers the internal os. Which of the following is the most appropriate next step in management?

Schedule elective cesarean delivery

Perform bimanual pelvic examination

Perform emergency cesarean delivery

Administer oxytocin to induce labor

A clinical diagnosis of abruptio placentae is suspected. Which of the following is the most appropriate next step in the management of this patient?

Administration of intravenous fluids

Administration of intravenous oxytocin

Administration of intramuscular betamethasone

Administration of intravenous tranexamic acid

A 31-year-old G3P0 is admitted to the hospital with profuse vaginal bleeding and abdominal pain at 34 weeks gestation. She reports passing bright blood with clots and no water in the discharge. She denies recent trauma or medical illnesses. She had no prenatal care. Her previous pregnancies culminated in spontaneous abortions in the second trimester. She has a 6-year history of drug abuse and cocaine smoking 2 hours prior to the onset of her symptoms. Her blood pressure is 160/90 mm Hg, the heart rate is 93/min, the respiratory rate is 19/min, and the temperature is 36.9℃ (98.4℉). The fetal heart rate is 110/min. On examination, the patient is lethargic. Her pupils are constricted, but reactive to light bilaterally. There are no signs of trauma. Abdominal palpation identifies lower abdominal tenderness and strong uterine contractions. The fundus of the uterus is between the xiphoid process and umbilicus. The patient’s perineum is grossly bloody. On pelvic examination, the vaginal canal is without lesions. The cervix is almost completely effaced and 2 cm dilated. Which of the following options is the most likely cause of the patient’s pregnancy-related condition?

Abrupt constriction of maternal and placental vessels

Thrombosis of the placental vessels

Dramatic decrease in thrombocytes

Premature rupture of the membranes

Rupture of the placental vessels

A 37-year-old woman, gravida 2, para 1, at 35 weeks' gestation is brought to the emergency department for the evaluation of continuous, dark, vaginal bleeding and abdominal pain for one hour. Her first child was delivered by lower segment transverse cesarean section because of a nonreassuring fetal heart rate. The patient has a history of hypertension and has been noncompliant with her hypertensive regimen. Her medications include methyldopa, folic acid, and a multivitamin. Her pulse is 90/min, respirations are 16/min, and blood pressure is 145/90 mm Hg. The abdomen is tender, and hypertonic contractions can be felt. There is blood on the vulva, the introitus, and on the medial aspect of both thighs. The fetus is in a breech presentation. The fetal heart rate is 180/min with recurrent decelerations. Which of the following is the cause of fetal compromise?

Placental tissue covering the cervical os

Rupture of aberrant fetal vessels

Placental abruption for USMLE Step 2 CK: High-Yield OB/GYN Lessons

Pathophysiology - The Great Separation

Primary Event: Rupture of maternal spiral arteries in the decidua basalis.
Hematoma Formation: Bleeding leads to a retroplacental hematoma.
- As the hematoma expands, it shears the placenta off the uterine wall.
- This separation severely compromises fetal oxygen and nutrient supply.
Bleeding Types:
- Revealed: Blood tracks down and drains through the cervix (visible bleeding).
- Concealed: Blood is trapped behind the placenta, with no visible external bleeding.

Concealed vs. Revealed Placental Abruption

⭐ Disseminated Intravascular Coagulation (DIC) is a major risk. Damaged decidual tissue releases large amounts of tissue factor (thromboplastin) into maternal circulation, triggering the coagulation cascade.

Risk Factors - Recipe for Disaster

Prior placental abruption: Strongest predictor, with a 10-15% recurrence risk.
Maternal hypertensive disorders:
- Chronic hypertension
- Preeclampsia / eclampsia
Trauma:
- Blunt abdominal trauma (e.g., MVA, falls, domestic violence)
Substance use:
- Cocaine (vasoconstriction)
- Tobacco smoking
Sudden uterine decompression:
- Amniorrhexis with polyhydramnios
- Delivery of the first twin
Other key factors:
- PPROM (Prelabor Rupture of Membranes)
- Advanced maternal age (AMA)
- Thrombophilias

⭐ A history of abruption in a previous pregnancy is the single most important risk factor.

Clinical Presentation - Code Red

Sudden-onset, severe abdominal pain or backache.
Painful, dark vaginal bleeding (⚠️ can be concealed in 20% of cases).
Uterine findings:
- Tender, firm-to-rigid consistency.
- High-frequency, low-amplitude contractions (tetanic).
Maternal instability:
- Tachycardia, hypotension (signs of shock).
- Risk of Disseminated Intravascular Coagulopathy (DIC).
Fetal distress:
- Non-reassuring fetal heart rate patterns (bradycardia, late decelerations).
- Sinusoidal pattern is an ominous sign.

⭐ High-Yield: The amount of visible vaginal bleeding does not correlate with the degree of maternal hemorrhage, as a significant volume can be trapped behind the placenta (concealed abruption).

Diagnosis & Management - Damage Control

Maternal Stabilization First: Priority is aggressive resuscitation.
- Secure airway; administer supplemental O₂.
- Place 2 large-bore IVs (≥16-gauge).
- Begin rapid infusion of crystalloids.
- Transfuse blood products (PRBCs, FFP, platelets) for hemorrhage & coagulopathy.

Placental Abruption with Retroplacental Hematoma

Delivery Decision Algorithm:

⭐ Be prepared for Disseminated Intravascular Coagulation (DIC). The large retroplacental hematoma releases tissue factor (thromboplastin), triggering a massive consumptive coagulopathy.

High‑Yield Points - ⚡ Biggest Takeaways

Painful third-trimester vaginal bleeding is the hallmark sign, unlike the painless bleeding of placenta previa.

Strongly associated with maternal hypertension, cocaine use, and abdominal trauma.

Diagnosis is clinical; ultrasound may show a retroplacental hematoma but is not sensitive.

Risk of Disseminated Intravascular Coagulation (DIC) from thromboplastin release.

Can present with a tender, rigid (hypertonic) uterus.

Management requires immediate C-section for fetal or maternal distress.

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