A 32-year-old primigravida at 28 weeks gestation presents with sudden-onset vaginal bleeding, abdominal pain, and uterine tenderness. Fetal heart rate is 110 bpm. What is the most common cause of antepartum hemorrhage in this clinical scenario?

Explanation

## Diagnosis of Abruptio Placentae **Key Point:** Abruptio placentae is the premature separation of a normally implanted placenta from the uterine wall before delivery of the fetus. It is the most common cause of antepartum hemorrhage in the second and third trimester, accounting for 20–25% of all APH cases. ### Clinical Presentation **High-Yield:** The classic triad of abruptio placentae is: 1. **Vaginal bleeding** (may be concealed in 10–20% of cases) 2. **Abdominal/uterine pain** (often severe and sudden) 3. **Uterine tenderness** (rigid, boardlike uterus in severe cases) The presence of all three features, especially with acute onset and uterine tenderness, is pathognomonic for placental abruption. ### Differential Diagnosis of APH Causes | Cause | Frequency | Presentation | Key Feature | |-------|-----------|--------------|-------------| | **Abruptio placentae** | 20–25% | Painful bleeding, uterine tenderness | Sudden onset, concealed bleeding possible | | Placenta previa | 20–25% | Painless bleeding | Recurrent episodes, no pain | | Subchorionic hemorrhage | 5–10% | Spotting, minimal pain | Self-limited, good prognosis | | Cervical causes | 10–15% | Painless, post-coital | Visible on speculum exam | **Clinical Pearl:** While placenta previa and abruptio placentae have similar overall frequencies, the **clinical presentation** distinguishes them: abruption is **painful with tenderness**; previa is **painless**. ### Why Abruptio Placentae in This Case The combination of: - Sudden-onset vaginal bleeding - **Abdominal pain** (distinguishes from previa) - **Uterine tenderness** (hallmark of abruption) - Viable fetus with preserved FHR (not yet in shock) This constellation is diagnostic of abruptio placentae, making it the most common cause in this clinical context. **Mnemonic:** **PAIN** = Placental Abruption Is the diagnosis with **P**ain, **A**cute onset, **I**ntrauterine bleeding, **N**ormal placental position. [cite:Obstetrics & Gynaecology by Hiralal Konar Ch 12]