From the Guidelines
Uterine atony is a condition where the uterus fails to contract effectively after childbirth, making it the leading cause of postpartum hemorrhage. It occurs when the uterine muscles lose their tone and ability to contract properly, preventing blood vessels from being compressed at the placental site 1. According to the most recent evidence, the most common cause of early postpartum hemorrhage is related to uterine atony or lack of effective uterine contraction after delivery 1.
Key Points
- Uterine atony is typically a clinical diagnosis in >75% of patients 1
- Treatment typically begins with uterotonic medications such as oxytocin, methylergonovine, carboprost, or misoprostol, and bimanual uterine massage 1
- Risk factors include prolonged labor, overdistended uterus, previous uterine atony, high parity, chorioamnionitis, and use of labor-augmenting medications
- The physiological basis involves exhaustion of the uterine muscle after prolonged contractions or stretching, disrupting the normal contraction mechanism needed to prevent excessive bleeding
Management
- Initial treatment should include uterotonic medications and bimanual uterine massage 1
- If bleeding persists, more invasive interventions may be necessary, including uterine tamponade with balloon devices, arterial embolization, or surgical options like B-Lynch sutures, uterine artery ligation, or hysterectomy in severe cases
- In cases of amniotic fluid embolism, anticipation of uterine atony, DIC, and hemorrhage is crucial, and the use of uterotonic agents, administration of tranexamic acid, and initiation of the hospital’s protocol for massive transfusion may reduce morbidity 1
From the FDA Drug Label
Uterine atony which has not responded to conventional methods of management For routine management of uterine atony, hemorrhage and subinvolution of the uterus
Uterine atony refers to a condition where the uterus fails to contract after delivery, leading to hemorrhage. It is a condition that may require medical intervention, such as the use of medications like carboprost tromethamine 2 or methylergonovine 3, to manage and control the bleeding. Key characteristics of uterine atony include:
- Failure of the uterus to contract after delivery
- Hemorrhage or excessive bleeding
- Lack of response to conventional methods of management, such as oxytocin or uterine massage
From the Research
Definition of Uterine Atony
- Uterine atony is defined as the failure of the uterus to contract following delivery, which is the most common cause of postpartum hemorrhage 4.
- It is a leading cause of maternal morbidity and mortality, and can be difficult to predict, even with risk assessment 5.
Causes and Risk Factors
- Risk factors for uterine atony include induced or augmented labor, preeclampsia, chorio-amnionitis, obesity, multiple gestation, polyhydramnios, and prolonged second stage of labor 5.
- Uterine atony can occur even in the absence of risk factors, making it challenging to predict and prevent 5.
Management and Treatment
- Oxytocin is the first-line drug for prevention and treatment of uterine atony, and is a routine component of the active management of the third stage of labor 5, 6.
- Second-line uterotonic agents include ergot alkaloids (ergometrine and methylergonovine) and the prostaglandins, carboprost and misoprostol, which work by a different mechanism to oxytocin and should be administered early for uterine atony refractory to oxytocin 5, 6, 7.
- Surgical and radiologic management of uterine atony includes uterine tamponade using balloon catheters and compression sutures, and percutaneous transcatheter arterial embolization 5, 8.
Prevention and Reduction of Morbidity
- Methylergonovine may be a more effective second-line uterotonic than carboprost, with a reduced risk of hemorrhage-related morbidity 7.
- Uterine compression suture technique can be used as an alternative to hysterectomy in the management of severe postpartum hemorrhage due to uterine atony, and can help save the uterus and facilitate quick and easy patient recovery 8.