Reproductive · Obstetric Hemorrhage
The facts most likely to be tested
The classic clinical presentation of abruptio placentae is painful vaginal bleeding accompanied by uterine tenderness and hypertonicity.
Maternal hypertension (chronic or gestational) and cocaine use are the most significant modifiable risk factors for placental abruption.
Abruptio placentae is a clinical diagnosis and should not be delayed by imaging if the patient is hemodynamically unstable or the fetus is in distress.
Couvelaire uterus is a life-threatening complication where blood infiltrates the myometrium, resulting in a firm, blue-purple uterus that may require hysterectomy.
Disseminated intravascular coagulation (DIC) is the most common systemic complication of severe abruption due to the release of tissue factor into the maternal circulation.
Fetal heart rate tracing abnormalities, such as late decelerations or bradycardia, are the most sensitive indicators of fetal compromise in the setting of abruption.
Immediate delivery is the definitive management for abruptio placentae if the fetus is mature or if there is evidence of fetal distress or maternal hemodynamic instability.
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A 28-year-old G2P1 woman at 34 weeks gestation presents to the emergency department with sudden onset of severe abdominal pain and dark red vaginal bleeding. She reports a history of poorly controlled chronic hypertension. On physical examination, the uterus is firm, tender, and hypertonic to palpation. Fetal heart rate monitoring reveals recurrent late decelerations and a baseline of 110 bpm. The patient is tachycardic, and her blood pressure is 150/95 mmHg.
What is the most likely diagnosis?
Abruptio placentae
The patient presents with the classic triad of painful vaginal bleeding, uterine tenderness, and hypertonicity, which is diagnostic of abruptio placentae, especially in the context of maternal hypertension.
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Etiology / Epidemiology
Primary risk factor is maternal hypertension (chronic or preeclampsia). Other risks include trauma, smoking, and cocaine use.
Clinical Manifestations
Classic triad: painful vaginal bleeding, abdominal pain, and uterine hypertonicity. Fetal distress is common.
Diagnosis
Diagnosis is clinical. Transabdominal ultrasound is used to rule out placenta previa, but has low sensitivity for abruption.
Treatment
Immediate delivery is the definitive treatment. Avoid tocolytics if fetal distress or maternal instability is present.
Prognosis
High risk of disseminated intravascular coagulation (DIC) and fetal demise. Maternal mortality is rare but fetal mortality is ~10-20%.
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Epidemiology & Etiology
Abruptio placentae is the premature separation of the placenta from the uterine wall after 20 weeks gestation. Maternal hypertension remains the most significant risk factor. Other major contributors include abdominal trauma, cocaine use, and a history of prior abruption.
Pertinent Anatomy
The placenta is a vascular organ attached to the decidua basalis. Separation disrupts the maternal-fetal interface, leading to hemorrhage that may be concealed or external.
Pathophysiology
Rupture of maternal vessels in the decidua basalis leads to blood accumulation between the placenta and uterine wall. This creates a retroplacental hematoma that can lead to uterine tetany and increased intrauterine pressure. The release of tissue factor into maternal circulation often triggers DIC.
Clinical Manifestations
Patients present with sudden-onset painful vaginal bleeding and a rigid, board-like abdomen. Fetal bradycardia or non-reassuring heart rate patterns are common due to placental insufficiency. The uterus is often tender and hypertonic, making palpation of fetal parts difficult.
Diagnosis
Diagnosis is primarily clinical based on the classic triad of symptoms. Transabdominal ultrasound is the gold standard to exclude placenta previa, though it fails to detect the majority of abruptions. Laboratory evaluation should include fibrinogen levels and PT/PTT to assess for coagulopathy.
Treatment
Management depends on gestational age and maternal/fetal stability. Immediate delivery is indicated for fetal distress or maternal hemodynamic instability. Avoid tocolytics as they may mask signs of labor. If the fetus is stable and preterm, corticosteroids may be administered for lung maturity.
Prognosis
The most feared complication is DIC, which occurs in severe cases due to massive tissue factor release. Fetal demise is a significant risk, necessitating continuous fetal monitoring. Patients require close observation for postpartum hemorrhage.
Differential Diagnosis
Placenta previa: painless, bright red bleeding
Vasa previa: fetal distress with rupture of membranes
Uterine rupture: loss of fetal station, history of C-section
Preterm labor: regular contractions without significant bleeding
Cervical insufficiency: painless cervical dilation