Uterine Atony: Symptoms, Causes, and Treatment

Overview

Uterine atony is a potentially life-threatening obstetric emergency characterized by the failure of the uterine muscles to contract adequately after delivery of the baby and placenta. This condition is the leading cause of postpartum hemorrhage worldwide, accounting for approximately 80% of all cases of severe postpartum bleeding.

Under normal circumstances, the uterus contracts vigorously after delivery to compress the blood vessels that previously supplied the placenta, thereby controlling bleeding. When uterine atony occurs, these contractions are weak or absent, allowing continued bleeding from the placental site. This can lead to rapid and severe blood loss, potentially resulting in hypovolemic shock and maternal mortality if not promptly recognized and treated.

The condition can occur immediately after delivery (primary postpartum hemorrhage) or within 24 hours to 12 weeks postpartum (secondary postpartum hemorrhage). Early recognition and immediate intervention are crucial for maternal safety. Risk factors include prolonged labor, multiple pregnancies, large babies, and certain medical conditions. With prompt medical attention and appropriate treatment, including uterotonic medications and sometimes surgical intervention, outcomes are generally favorable.

Understanding the signs and symptoms of uterine atony is essential for new mothers and their families, as well as healthcare providers, to ensure rapid response when this emergency occurs. The condition requires immediate medical intervention and is typically managed in hospital settings with specialized obstetric care.

Symptoms

The symptoms of uterine atony typically develop during or immediately after childbirth, though they can also occur weeks later. The primary concern is excessive bleeding that doesn't respond to normal postpartum care measures.

Primary Symptoms

Additional Warning Signs

Lower abdominal pain that is severe and persistent
Blood in urine or difficulty urinating
Intermenstrual bleeding patterns
Pain during pregnancy that worsens
Problems during pregnancy requiring immediate attention

Signs of Severe Blood Loss

When uterine atony leads to significant hemorrhage, patients may experience:

Rapid heart rate (tachycardia)
Low blood pressure (hypotension)
Weakness and fatigue
Dizziness or lightheadedness
Pale skin and mucous membranes
Cold, clammy skin
Shortness of breath
Decreased urine output
Confusion or altered mental state

Physical Examination Findings

Healthcare providers may identify:

Soft, boggy uterus that fails to contract
Uterine fundus above the umbilicus
Continuous vaginal bleeding
Large blood clots
Signs of hypovolemic shock

Causes

Uterine atony occurs when the myometrium (uterine muscle) fails to contract effectively after delivery. Several factors can contribute to this condition, often categorized using the "4 Ts" mnemonic: Tone, Tissue, Trauma, and Thrombin.

Tone-Related Causes

Problems with uterine muscle contraction:

Uterine overdistension from multiple pregnancies, large babies, or excess amniotic fluid
Prolonged or precipitous labor
Use of certain medications during labor (magnesium sulfate, nifedipine)
Maternal exhaustion from prolonged labor
General or regional anesthesia effects
Uterine muscle fatigue

Tissue-Related Causes

Retained products preventing proper uterine contraction:

Retained placental fragments
Placenta accreta, increta, or percreta
Placental abruption
Invasive mole or choriocarcinoma
Uterine fibroids

Trauma-Related Causes

Physical damage to the reproductive tract:

Uterine rupture
Cervical lacerations
Vaginal or perineal tears
Operative delivery trauma
Previous uterine surgery or cesarean section

Thrombin-Related Causes

Coagulation disorders affecting clotting:

Disseminated intravascular coagulation (DIC)
Inherited bleeding disorders
Severe preeclampsia or HELLP syndrome
Anticoagulant medications
Liver disease affecting clotting factors

Risk Factors

Several maternal and obstetric factors increase the risk of developing uterine atony:

Maternal Risk Factors

Previous history of postpartum hemorrhage
Multiple previous pregnancies (grand multiparity)
Advanced maternal age (over 35 years)
Obesity (BMI >30)
Maternal anemia
Bleeding disorders or anticoagulant use
Uterine fibroids or structural abnormalities
History of retained placenta

Pregnancy-Related Risk Factors

Multiple gestations (twins, triplets)
Macrosomia (large baby over 4000g)
Polyhydramnios (excess amniotic fluid)
Pregnancy-induced hypertension
Placental abnormalities (previa, abruption)
Chorioamnionitis (uterine infection)

Labor and Delivery Risk Factors

Prolonged labor (over 20 hours in first-time mothers)
Precipitous delivery (very rapid labor)
Operative delivery (forceps, vacuum, cesarean)
Use of labor-augmenting medications
General anesthesia
Prolonged third stage of labor
Manual removal of placenta

Medication-Related Risk Factors

Magnesium sulfate therapy
Calcium channel blockers
Nitroglycerin
General anesthetic agents
High-dose oxytocin during labor

Diagnosis

Diagnosing uterine atony requires prompt clinical assessment, particularly in the setting of postpartum hemorrhage. The diagnosis is primarily clinical, based on physical examination and assessment of bleeding patterns.

Clinical Assessment

Uterine palpation: Soft, boggy uterus that doesn't contract with massage
Fundal height: Uterus remains high and doesn't descend appropriately
Bleeding assessment: Quantification of blood loss (>500ml vaginal delivery, >1000ml cesarean)
Vital signs monitoring: Blood pressure, heart rate, oxygen saturation
Visual inspection: Assessment of genital tract for trauma

Laboratory Tests

Complete blood count (CBC) to assess hemoglobin and platelet levels
Coagulation studies (PT, PTT, INR, fibrinogen)
Blood type and crossmatch for potential transfusion
Basic metabolic panel
Arterial blood gas if shock is suspected
D-dimer and other DIC markers if indicated

Imaging Studies

While diagnosis is primarily clinical, imaging may be helpful in certain cases:

Pelvic ultrasound to assess for retained products
CT scan if intra-abdominal bleeding is suspected
MRI in cases of suspected placental abnormalities

Differential Diagnosis

Other causes of postpartum hemorrhage to consider:

Genital tract trauma (lacerations, hematomas)
Retained placental tissue
Coagulation disorders
Uterine rupture
Uterine inversion

Treatment Options

Treatment of uterine atony is a medical emergency requiring immediate intervention to control bleeding and prevent maternal morbidity and mortality. Management follows a stepwise approach from conservative measures to surgical intervention.

Initial Emergency Management

Call for help: Activate emergency response team
IV access: Establish large-bore intravenous lines
Blood samples: Type and crossmatch, complete blood count, coagulation studies
Oxygen therapy: Maintain adequate oxygenation
Vital signs monitoring: Continuous monitoring of blood pressure, heart rate

First-Line Medical Treatment

Uterotonic Medications:

Oxytocin: 10-40 units in 1000ml normal saline, infused rapidly
Methylergonovine: 0.2mg intramuscularly (contraindicated in hypertension)
Carboprost (Hemabate): 250mcg intramuscularly every 15-90 minutes
Misoprostol: 600-1000mcg sublingually or rectally

Physical Interventions

Uterine massage: Bimanual uterine compression
Bladder emptying: Foley catheter placement
Uterine exploration: Manual removal of retained products
External aortic compression: Temporary measure during preparation for surgery

Second-Line Interventions

Intrauterine balloon tamponade: Bakri balloon or condom catheter
Compression sutures: B-Lynch, Cho, or Hayman sutures
Pelvic vessel ligation: Uterine or internal iliac artery ligation
Interventional radiology: Arterial embolization

Surgical Management

Reserved for cases unresponsive to conservative management:

Hysterectomy: Last resort for life-threatening hemorrhage
Subtotal vs. total: Subtotal preferred for faster procedure
Timing: Should not be delayed if other measures fail

Supportive Care

Blood transfusion: Packed red blood cells, fresh frozen plasma, platelets
Massive transfusion protocol: For severe hemorrhage
Correction of coagulopathy: Factor replacement as needed
Intensive care monitoring: For hemodynamically unstable patients

Prevention

While not all cases of uterine atony can be prevented, several strategies can reduce the risk and improve outcomes when this complication occurs.

Prenatal Prevention

Risk assessment: Identify high-risk pregnancies early
Anemia treatment: Correct iron deficiency before delivery
Management of comorbidities: Control diabetes, hypertension
Birth planning: Delivery at appropriate level of care
Patient education: Awareness of warning signs

Intrapartum Prevention

Active management of third stage: Routine oxytocin administration
Controlled cord traction: Proper delivery of placenta
Avoid unnecessary interventions: Minimize trauma and exhaustion
Monitor labor progress: Prevent prolonged labor when possible
Adequate anesthesia: Avoid excessive medication that impairs contractions

Active Management Protocol

Routine use of active management reduces hemorrhage risk by 60%:

Oxytocin 10 units intramuscularly or intravenously
Controlled cord traction after signs of placental separation
Uterine massage after placental delivery
Early clamping and cutting of umbilical cord

Facility Preparedness

Emergency protocols: Written guidelines and regular drills
Medication availability: Uterotonic drugs readily available
Blood bank: Type and screen for high-risk patients
Surgical backup: Operating room and anesthesia available
Team training: Regular obstetric emergency simulations

High-Risk Patient Management

Delivery planning at tertiary care center
Intravenous access established early in labor
Blood type and crossmatch available
Anesthesia consultation
Multidisciplinary team involvement

When to See a Doctor

Uterine atony is a medical emergency that requires immediate professional intervention. Understanding when to seek help can be life-saving.

Emergency Situations - Call 911

Heavy bleeding that soaks through a pad in one hour or less
Passing large blood clots (larger than a golf ball)
Severe abdominal or pelvic pain
Signs of shock: dizziness, weakness, rapid heartbeat, confusion
Fainting or loss of consciousness
Difficulty breathing or chest pain
Sudden severe back pain

Seek Immediate Medical Attention

Prolonged bleeding after delivery (more than normal lochia)
Foul-smelling vaginal discharge
Fever above 100.4°F (38°C)
Severe cramping that doesn't improve with pain medication
Inability to urinate or painful urination
Persistent nausea and vomiting
Severe headache or vision changes

For Healthcare Providers

Healthcare providers should maintain high suspicion for uterine atony in:

Any patient with postpartum bleeding exceeding normal parameters
Soft, boggy uterus on examination
Failure of uterus to contract with massage
High-risk patients during delivery
Any signs of hemodynamic instability postpartum

Follow-up Care

After treatment for uterine atony, patients should:

Attend all scheduled postpartum visits
Monitor for delayed complications
Report any unusual bleeding or symptoms
Discuss future pregnancy planning with healthcare provider
Consider counseling for birth trauma if needed

Related Conditions

Uterine atony is associated with several obstetric complications and related conditions:

Other Related Conditions

References

American College of Obstetricians and Gynecologists. Practice Bulletin No. 183: Postpartum Hemorrhage. Obstet Gynecol. 2017;130(4):e168-e186.
World Health Organization. WHO recommendations for the prevention and treatment of postpartum haemorrhage. Geneva: WHO Press; 2012.
Society for Maternal-Fetal Medicine. Electronic address: [email protected]. SMFM Statement on postpartum hemorrhage. Am J Obstet Gynecol. 2015;212(3):272-4.
Begley CM, Gyte GM, Devane D, McGuire W, Weeks A. Active versus expectant management for women in the third stage of labour. Cochrane Database Syst Rev. 2019;2:CD007412.
Bais JM, Eskes M, Pel M, Bonsel GJ, Bleker OP. Postpartum haemorrhage in nulliparous women: incidence and risk factors in low and high risk women. Eur J Obstet Gynecol Reprod Biol. 2004;115(2):166-72.

Uterine Atony

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