Reproductive · Obstetric Emergencies
The facts most likely to be tested
Uterine atony is the most common cause of postpartum hemorrhage (PPH), characterized by a boggy, enlarged uterus on bimanual examination.
First-line management for uterine atony is bimanual uterine massage and uterotonic agents such as oxytocin.
Methylergonovine is contraindicated in patients with hypertension or preeclampsia due to the risk of inducing severe vasoconstriction.
Carboprost tromethamine (a prostaglandin F2α analog) is contraindicated in patients with asthma due to the risk of bronchospasm.
Tranexamic acid is an antifibrinolytic agent that should be administered intravenously within 3 hours of birth to reduce mortality in PPH.
Placenta accreta spectrum (accreta, increta, percreta) is strongly associated with a history of prior cesarean section and placenta previa.
Uterine inversion presents as a smooth, round mass protruding through the cervix or vagina and requires immediate manual replacement.
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A 28-year-old G2P2 woman undergoes an uncomplicated spontaneous vaginal delivery of a 4,000g infant. Ten minutes later, she develops heavy vaginal bleeding. On physical examination, the patient is tachycardic and hypotensive. The uterus is soft, boggy, and palpated above the umbilicus. The patient has a history of well-controlled asthma.
What is the most appropriate next step in the management of this patient's condition?
Uterine massage and administration of oxytocin
The patient presents with classic signs of uterine atony. While methylergonovine and carboprost are second-line uterotonics, carboprost is contraindicated due to her asthma, and oxytocin is the first-line agent for atony.
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Etiology / Epidemiology
Defined as blood loss >1000 mL or signs of hypovolemia within 24 hours. Uterine atony is the most common cause.
Clinical Manifestations
Presents as boggy uterus and excessive vaginal bleeding. Tachycardia and hypotension are late signs of shock.
Diagnosis
Clinical diagnosis based on visual estimation of blood loss. Transvaginal ultrasound is used to rule out retained products.
Treatment
First-line is bimanual uterine massage and oxytocin. Methylergonovine is contraindicated in hypertension.
Prognosis
Most cases resolve with conservative management. Sheehan syndrome is a rare, life-long complication of severe hypotension.
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Epidemiology & Etiology
PPH is the leading cause of maternal mortality worldwide. The '4 Ts' mnemonic guides etiology: Tone (atony), Trauma (lacerations), Tissue (retained placenta), and Thrombin (coagulopathy). Multiparity and prolonged labor are major risk factors.
Pertinent Anatomy
The myometrium acts as a physiological ligature for spiral arteries. Failure of these muscle fibers to contract leads to uncontrolled hemorrhage from the placental implantation site.
Pathophysiology
Uterine atony results from overdistension, exhaustion, or infection. Without sustained contraction, the spiral arteries remain patent, leading to rapid exsanguination. Coagulopathy may develop secondary to massive blood loss and consumption of clotting factors.
Clinical Manifestations
Patients present with heavy vaginal bleeding and a boggy uterus on palpation. Tachycardia and narrowing pulse pressure are early indicators of hemodynamic instability. Watch for placenta accreta if the placenta fails to separate spontaneously.
Diagnosis
Diagnosis is primarily clinical. Quantitative blood loss (QBL) is preferred over visual estimation. Transvaginal ultrasound is the gold standard to identify retained products of conception if the uterus is empty but bleeding persists.
Treatment
Initial management includes bimanual uterine massage and IV oxytocin. Second-line agents include methylergonovine (contraindicated in hypertension) or carboprost (contraindicated in asthma). Surgical intervention includes uterine artery embolization or, as a last resort, hysterectomy.
Prognosis
Early recognition prevents hypovolemic shock. Long-term sequelae include Sheehan syndrome, characterized by pituitary necrosis and subsequent lactation failure.
Differential Diagnosis
Uterine Atony: soft, boggy uterus
Genital Tract Laceration: firm uterus with bright red bleeding
Retained Placenta: incomplete placental delivery
Uterine Inversion: fundal collapse through the cervix
Coagulopathy: generalized oozing from IV sites