Uterine Atony — The Leading Cause of Postpartum Hemorrhage
Loss of myometrial tone prevents natural vessel clamping after birth.
- ~70%: PPH cause share (Placeholder statistic)
- <1 min: Normal tone onset (Placeholder statistic)
- 12+: Risk factor count (Placeholder statistic)
- Soft/boggy: Fundal check (Placeholder finding)
Mechanism of atony
Overdistended or exhausted uterine muscle fails to contract.
Placeholder callout: early fundal massage detects atony fast.
Continued Bleeding from the Placental Implantation Site
Without contraction, spiral arteries continue to hemorrhage freely.
- 500-1000 mL/min: Flow rate (Placeholder statistic)
- Minutes: Time to shock (Placeholder statistic)
- Spiral arteries: Vessel type (Placeholder detail)
- Steady flow: Detection cue (Placeholder finding)
Why bleeding persists
Vessels stay open until myometrial fibers compress them shut.
Placeholder callout: quantify blood loss early and often.
Oxytocin — First-Line Uterotonic Therapy
Oxytocin receptor binding drives rhythmic myometrial contraction.
- IV infusion: Route (Placeholder detail)
- ~1 min: Onset (Placeholder statistic)
- First-line: Guideline status (Placeholder detail)
- ~80-90%: Response rate (Placeholder statistic)
Oxytocin mechanism
Receptor activation raises intracellular calcium, triggering contraction.
Placeholder callout: oxytocin is standard prophylaxis and treatment.
Second-Line Uterotonics — Methylergonovine and Misoprostol
Added when oxytocin alone fails to achieve adequate tone.
- IM route: Methylergonovine (Placeholder detail)
- Rectal/oral: Misoprostol (Placeholder detail)
- Hypertension: Contraindication (Placeholder caution)
- ~95%: Combined success (Placeholder statistic)
Escalation logic
Stepwise addition of agents targets different receptor pathways.
Placeholder callout: check blood pressure before ergot agents.
Bimanual Uterine Massage — Mechanical Adjunct
Manual compression buys time while pharmacologic agents take effect.
- Two-hand compression: Technique (Placeholder detail)
- Until tone returns: Duration (Placeholder detail)
- Bridge therapy: Adjunct role (Placeholder detail)
- Improved hemostasis: Combined effect (Placeholder finding)
Manual compression
External and internal hand compress uterus against sacrum.
Placeholder callout: massage complements, not replaces, drugs.