uterine atony
Pronunciation: AT-oh-nee
Failure of the uterine muscle to contract adequately after delivery, leading to postpartum hemorrhage. The most common cause of primary PPH.
Full Definition
A condition characterized by the inability of the uterine muscle to contract effectively following delivery of the placenta, resulting in continued bleeding from placental implantation sites. Uterine atony is the most common cause of primary postpartum hemorrhage, accounting for approximately 80% of cases. Normally, uterine contractions compress the spiral arteries and control bleeding after placental separation, but in atony, the muscle fibers fail to maintain adequate tension. Risk factors include prolonged labor, multiple gestation, polyhydramnios, large fetus, multiparity, use of uterine relaxants, and chorioamnionitis. Clinical presentation includes a soft, boggy uterus that fails to contract with massage and excessive vaginal bleeding. Treatment involves uterine massage, pharmacological agents (oxytocin, methylergonovine, prostaglandins), and potentially surgical intervention if conservative measures fail.
Usage
Usage note: Always describe uterine consistency (soft, boggy, firm) when documenting atony. Distinguish from other causes of PPH.
In Context
- "Uterine atony was evident by the soft, boggy fundus and continued bleeding." — Postpartum assessment
- "Treatment of uterine atony included bimanual compression and intravenous oxytocin." — Emergency management note