A 28-year-old multiparous woman at 28 weeks gestation presents with vaginal bleeding and severe abdominal pain. Diagnosis of placental abruption is confirmed. She is hypotensive (BP 90/60 mmHg), tachycardic (HR 118/min), and shows signs of disseminated intravascular coagulation (DIC) with prolonged PT, aPTT, and low fibrinogen. What is the drug of choice for immediate management of uterine atony and control of postpartum haemorrhage?

## Management of Uterine Atony and Postpartum Haemorrhage ### Clinical Context This patient has **severe placental abruption with DIC** and haemodynamic instability. After emergency delivery, the primary goal is to control uterine atony-related postpartum haemorrhage (PPH). The question asks for the **drug of choice** for immediate management of uterine atony and PPH control. ### Why Oxytocin is the Drug of Choice **Key Point:** **Oxytocin** is universally recognised as the **first-line uterotonic agent** for prevention and treatment of PPH due to uterine atony, as endorsed by WHO, FIGO, RCOG, and ACOG guidelines. 1. **Rapid onset:** IV oxytocin acts within 1–2 minutes; IM within 3–5 minutes 2. **Established efficacy:** Reduces PPH risk by ~50% compared to no uterotonic 3. **First-line in all settings:** Recommended regardless of coagulation status as the initial agent 4. **Standard of care:** Given routinely at the time of delivery of the anterior shoulder or immediately after delivery of the placenta 5. **Dose:** 10 IU IM or 5 IU slow IV bolus, followed by infusion of 20–40 IU in 500 mL NS at 125 mL/hr ### Comparison of Uterotonic Agents | Agent | Role | Notes | |-------|------|-------| | **Oxytocin** | **First-line DOC** | Rapid onset, WHO-recommended, universal first-line | | **Carboprost (PGF2α)** | Second-line / adjunct | Used when oxytocin fails; contraindicated in asthma | | **Misoprostol** | Alternative when oxytocin unavailable | Slower onset, less reliable in acute severe bleeding | | **Nifedipine** | Tocolytic (calcium channel blocker) | NOT a uterotonic; has no role in PPH management | **High-Yield (Harrison's / Williams Obstetrics):** Oxytocin is the **drug of choice** for uterine atony and PPH. Carboprost is a **second-line agent** used when oxytocin (with or without ergometrine) fails to control haemorrhage. The presence of DIC does not change the first-line choice — oxytocin is still initiated first, with carboprost added if needed. ### Why Other Options Are Incorrect - **Carboprost (C):** A potent second-line prostaglandin uterotonic, but NOT the first-line drug of choice. Reserved for oxytocin-refractory PPH. - **Misoprostol (B):** Useful when oxytocin is unavailable; slower onset and less reliable in acute severe haemorrhage. - **Nifedipine (D):** A calcium channel blocker used as a tocolytic and antihypertensive. It has **no role** in PPH management and would worsen hypotension in this patient. **Clinical Pearl:** Per Williams Obstetrics (25th ed.) and WHO PPH guidelines, **oxytocin 10 IU IM or IV** is the universal first-line uterotonic for PPH due to uterine atony. Carboprost is escalated as a second-line agent when oxytocin fails.