## Distinguishing Features: Abruptio Placentae vs Placenta Previa ### Key Clinical Discriminator **Key Point:** Uterine tenderness with board-like (woody) rigidity is the hallmark of abruptio placentae and is ABSENT in placenta previa. This reflects placental separation and concealed hemorrhage into the myometrium. ### Comparative Table | Feature | Abruptio Placentae | Placenta Previa | | --- | --- | --- | | **Uterine tenderness** | Present (hallmark) | Absent | | **Uterine consistency** | Board-like, rigid | Soft, normal | | **Vaginal bleeding** | May be concealed (70%) | Always visible | | **Abdominal pain** | Severe, constant | Absent | | **Fetal heart rate** | Often abnormal (bradycardia) | Usually normal | | **Maternal shock** | Early (concealed bleed) | Late (visible bleed) | | **Coagulopathy** | Common (DIC) | Rare | ### Why Uterine Tenderness Matters **High-Yield:** In abruptio placentae, the placenta separates from the decidua, and blood accumulates between the placenta and uterine wall. This causes: 1. Myometrial irritation → tenderness 2. Uterine muscle contraction → board-like rigidity 3. Concealed hemorrhage → maternal shock without proportionate visible bleeding In placenta previa, the placenta is implanted over the internal cervical os but remains attached to the endometrium. The uterus is soft and non-tender because there is no separation or myometrial infiltration. **Clinical Pearl:** A tender, rigid uterus with vaginal bleeding = abruptio placentae until proven otherwise. This finding alone warrants immediate delivery consideration regardless of gestational age. **Mnemonic — APH Severity Signs:** **CRAB** - **C**oncealed bleeding (70% in severe abruption) - **R**igid uterus (board-like) - **A**bdominal pain (severe) - **B**radycardia (fetal distress) Placenta previa presents with **painless** vaginal bleeding and a **soft** uterus.
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