What is the management for uterine atony?

Management of Uterine Atony

Begin immediately with bimanual uterine massage to stimulate contractions, followed by oxytocin as first-line pharmacologic therapy. 1

Initial Assessment and Mechanical Management

• Uterine massage is the immediate first step to stimulate myometrial contractions and should be performed while preparing pharmacologic interventions 1
• Verify complete placental delivery, as retained products prevent effective uterine contraction 2
• Thoroughly inspect the cervix and vagina to rule out lacerations that may contribute to bleeding, as genital tract trauma can coexist with or mimic atony 1

First-Line Pharmacologic Treatment: Oxytocin

Oxytocin is the first-line uterotonic agent for both prevention and treatment of uterine atony. 3, 4

Dosing for Postpartum Hemorrhage:

• Intravenous infusion: Add 10-40 units of oxytocin to 1,000 mL of non-hydrating diluent and run at a rate necessary to control uterine atony 3
• Intramuscular administration: 10 units can be given after delivery of the placenta 3
• For women undergoing intrapartum cesarean delivery, higher bolus doses (3 IU) or infusion rates are recommended compared to elective procedures 4

Second-Line Uterotonic Agents

If uterine atony is refractory to oxytocin, administer second-line agents early—methylergonovine and carboprost are likely superior to misoprostol. 4, 5

Methylergonovine (Ergot Alkaloid):

• Indicated for routine management of uterine atony and hemorrhage following placental delivery 6
• Contraindicated in hypertensive patients due to risk of severe vasoconstriction and hypertensive crisis 1
• Works by a different mechanism than oxytocin, making it effective for oxytocin-refractory cases 4

Carboprost (Prostaglandin):

• Indicated for postpartum hemorrhage due to uterine atony that has not responded to conventional methods, including oxytocin and uterine massage 7
• Prior treatment should include intravenously administered oxytocin and manipulative techniques before carboprost administration 7
• Has resulted in satisfactory control of hemorrhage and avoidance of emergency surgical intervention in high proportion of cases 7

Misoprostol:

• Recent studies question its effectiveness as an adjunct to other uterotonics, but remains useful in resource-limited settings 4, 5

Concurrent Hemorrhage Management

Administer tranexamic acid (TXA) 1 gram IV over 10 minutes immediately when postpartum hemorrhage is diagnosed, as effectiveness declines by 10% for every 15 minutes of delay. 8

• TXA reduces bleeding-related mortality when given within 3 hours of delivery and should be part of the first-response bundle 8
• Implement early aggressive resuscitation with blood products (packed red cells, fresh-frozen plasma, and platelets at a 1:1:1 ratio) in cases of massive hemorrhage 1
• Monitor for hypofibrinogenemia (occurs in 17% of cases with blood loss >2000 mL); consider early fibrinogen replacement with cryoprecipitate if levels <2-3 g/L with ongoing bleeding 8

Advanced Interventions for Refractory Atony

For uterine atony unresponsive to medical management, proceed to uterine tamponade before considering surgical options. 1

Uterine Tamponade:

• Intrauterine balloon catheters or packing can be used for refractory uterine atony 1, 4

Surgical Options (in order of escalation):

1. Bilateral uterine artery ligation (though efficacy may be limited by collateral circulation) 1, 8
2. B-Lynch compression suture or other uterine compression techniques 1
3. Uterine artery embolization may be considered in hemodynamically stable patients who have failed medical management and non-surgical interventions 8
4. Hysterectomy is reserved as the last resort when all other measures have failed 1, 8

Critical Pitfalls to Avoid

• Never administer methylergonovine to hypertensive patients—this is an absolute contraindication due to risk of severe hypertensive crisis 1
• Do not delay second-line uterotonic agents; administer early when oxytocin proves inadequate 4
• Avoid misdiagnosing amniotic fluid embolism based solely on hemorrhage from persistent atony with secondary coagulopathy 1
• Do not overlook genital tract lacerations as a concurrent or alternative source of bleeding 1, 2
• Assess for coagulopathy, which may develop following cardiovascular collapse or massive transfusion 9, 1