## Distinguishing Uterine Atony from Placental Abruption ### Key Discriminating Feature **Key Point:** Uterine consistency and contractility on palpation is the single best clinical discriminator between these two causes of early postpartum hemorrhage. ### Comparative Table | Feature | Uterine Atony | Placental Abruption | | --- | --- | --- | | **Uterine feel** | Soft, boggy, poorly contracted | Firm, tender, woody consistency | | **Abdominal pain** | Absent or mild | Severe, constant | | **Vaginal bleeding** | Brisk, continuous | May be concealed or mixed | | **Placenta delivery** | Usually normal | Often retained or fragmented | | **Coagulopathy** | Absent (early) | Present (DIC common) | | **Vital signs** | Variable with blood loss | Early shock despite smaller visible loss | ### Clinical Pearl **Clinical Pearl:** A soft, boggy, non-contracting uterus is pathognomonic for atony. Fundal massage and oxytocin cause rapid improvement. In abruption, the uterus remains firm and tender despite oxytocin, and the patient deteriorates due to concealed hemorrhage and DIC. ### High-Yield Distinction **High-Yield:** Uterine palpation findings are immediate, bedside, and require no investigation — making them the most practical discriminator in the first minutes of hemorrhage management. ### Pathophysiology 1. **Uterine atony:** Loss of myometrial contractility → open venous sinuses bleed freely → visible hemorrhage dominates. 2. **Placental abruption:** Premature placental separation → concealed bleeding into myometrium → uterine wall becomes tense and firm from intrauterine hematoma. **Mnemonic:** ATONY = **A**bsent **T**one, **O**pen **N**eed for oxytocin, **Y**ield to massage.
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