Uterine atony

Uterine atony
Atonic uterus (held by surgeon)
Specialty	Obstetrics
Symptoms	Uncontrolled postpartum bleeding, decreased heart rate, pain, soft non-contracted uterus
Complications	postpartum hemorrhage, DIC, hypovolemic shock, renal failure, hepatic failure, and death
Usual onset	third stage of labor
Causes	trauma, complicated labor, medications, uterine distention, caesarean section
Risk factors	Obesity, uterine distention, placental disorders, multiple gestation, prior PPH, coagulopathies
Diagnostic method	Physical exam and observed blood loss
Differential diagnosis	uterine inversion, obstetric laceration
Prevention	Risk stratification and identification, active management of third stage of labor
Treatment	Uterine massage, Oxytocin, uterotonics, tamponade or packing, surgical intervention
Medication	Oxytocin (Pitocin), Carbetocin, Methergine, Hemabate or Carboprost, Misoprostol, Dinoprostone
Prognosis	2-3 times risk of recurrence
Frequency	80% of postpartum bleeding

Uterine atony is the failure of the uterus to contract adequately following delivery. Contraction of the uterine muscles during labor compresses the blood vessels and slows flow, which helps prevent hemorrhage and facilitates coagulation. Therefore, a lack of uterine muscle contraction can lead to an acute hemorrhage, as the vasculature is not being sufficiently compressed.^[1] Uterine atony is the most common cause of postpartum hemorrhage, which is an emergency and potential cause of fatality. Across the globe, postpartum hemorrhage is among the top five causes of maternal death.^[2] Recognition of the warning signs of uterine atony in the setting of extensive postpartum bleeding should initiate interventions aimed at regaining stable uterine contraction.