Management of Premature Uterine Contractions
Tocolytic medications, particularly terbutaline, are the most effective first-line treatment for stopping premature uterine contractions when intervention is necessary, though they typically only delay delivery for 24-48 hours. 1, 2
Initial Assessment and Management
When a patient presents with premature uterine contractions, follow this approach:
Determine if intervention is necessary:
First-line interventions:
- Hydration and rest assessment: While commonly used, IV hydration alone has not been proven effective in prolonging pregnancy compared to observation 3, 4
- Terbutaline administration: 0.25 mg subcutaneously can effectively stop contractions quickly (within approximately 4 hours vs. 5-6 hours for observation or hydration) 3
Medication Options
Beta-adrenergic Receptor Agonists (First-line)
- Terbutaline: 0.25 mg subcutaneously 3
- Effectiveness: Effectively stops contractions for 24-48 hours 2
- Side effects: Maternal tachycardia (occurs in about 15% of patients) 5
Magnesium Sulfate
- Not recommended as primary tocolytic: Research shows it is not better than placebo for treating premature labor 2
- Dosing if used: Must be diluted to 20% or less for IV infusion 6
- Monitoring: Requires close monitoring of patellar reflexes, respiratory rate (should remain ≥16 breaths/min), and serum magnesium levels (3-6 mg/100mL) 6
- Caution: Risk of magnesium toxicity, especially with renal impairment; calcium should be immediately available to counteract toxicity 6
Other Options
- Prostaglandin inhibitors: May be effective with fewer side effects 2
- Calcium channel blockers: Can inhibit contractions but role in stopping labor is not well-defined 2
- Oxytocin antagonists: Should only be used in experimental clinical trials 2
Special Considerations
Intrauterine Resuscitation for Fetal Distress
If fetal distress is present during contractions:
- Position mother in left lateral position to avoid aortocaval compression 7
- Consider terbutaline to transiently stop contractions 1
- Note that routine supplemental oxygen has no proven benefit 7
Contraindications to Tocolysis
- Evidence of cephalopelvic disproportion (CPD) 1
- Advanced cervical dilation
- Maternal conditions where prolonging pregnancy is contraindicated
Follow-up Management
- Patients who respond to initial management but don't require tocolytics still have a 2.6-fold increased risk of delivering prematurely compared to the general population 8
- Monitor these patients as high-risk, even if initial contractions resolve 8
- For patients between 24-32 weeks gestation who continue to have progressive cervical change, consider IV tocolysis 2
Key Pitfalls to Avoid
- Do not use magnesium sulfate as primary tocolytic therapy 2
- Avoid excessive IV hydration before administering tocolytics, as this increases risk of pulmonary edema 4
- Remember that tocolytics typically only delay delivery for 24-48 hours - use this time for administration of corticosteroids for fetal lung maturity 2
- Do not continue tocolytic therapy beyond 5-7 days due to potential fetal risks 6