Uterine atony

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Uterine atony is a medical condition characterized by the failure of the uterus to contract adequately after childbirth. This condition can lead to severe postpartum hemorrhage, which is a significant cause of maternal morbidity and mortality.

Pathophysiology

The uterus is a muscular organ that contracts to help expel the placenta and reduce bleeding after delivery. In cases of uterine atony, the myometrium (the muscular layer of the uterus) fails to contract effectively. This lack of contraction can result in excessive bleeding, as the blood vessels at the placental site remain open.

Causes

Several factors can contribute to uterine atony, including:

• Overdistension of the uterus due to multiple pregnancies, polyhydramnios, or a large baby.
• Prolonged labor or rapid labor.
• Use of tocolytics or magnesium sulfate.
• High parity (having given birth multiple times).
• Chorioamnionitis (infection of the fetal membranes).
• Uterine fibroids.

Diagnosis

The diagnosis of uterine atony is primarily clinical. It is suspected when there is excessive bleeding after delivery and the uterus feels soft and boggy upon palpation. Ultrasound may be used to rule out retained placental fragments or other causes of bleeding.

Management

Management of uterine atony involves several steps:

• Uterine massage to stimulate contractions.
• Administration of uterotonic drugs such as oxytocin, ergometrine, or misoprostol.
• Bimanual compression of the uterus.
• In severe cases, surgical interventions such as uterine artery embolization, compression sutures, or hysterectomy may be necessary.

Prevention

Preventive measures include the active management of the third stage of labor, which involves the administration of uterotonic drugs immediately after the delivery of the baby to promote uterine contractions and reduce the risk of uterine atony.

Prognosis

With prompt and effective management, the prognosis for uterine atony is generally good. However, if not treated promptly, it can lead to severe complications, including hypovolemic shock, coagulopathy, and even maternal death.

See also

• Postpartum hemorrhage
• Uterotonic
• Hysterectomy
• Placenta