Can terbutaline be used as a short‑term tocolytic for preterm uterine contractions in pregnancy, and what are the recommended dosing, maximum duration, contraindications, and alternative agents?

Terbutaline for Preterm Labor: Clinical Recommendations

Primary Recommendation

Terbutaline can be used as a short-term tocolytic (≤48-72 hours only) for preterm uterine contractions, but nifedipine and indomethacin are preferred first-line agents. 1, 2 The FDA has issued a black box warning explicitly stating that terbutaline should NOT be used for prolonged tocolysis beyond 48-72 hours due to serious adverse reactions including maternal death, cardiac arrhythmias, pulmonary edema, and myocardial ischemia. 3, 4

FDA-Mandated Contraindications and Warnings

Terbutaline is absolutely contraindicated for:

• Prolonged tocolysis beyond 48-72 hours 3, 4
• Maintenance tocolysis in outpatient or home settings 3, 4
• Patients with hypersensitivity to sympathomimetic amines 4

Serious maternal adverse reactions include: increased heart rate, transient hyperglycemia, hypokalemia, cardiac arrhythmias, pulmonary edema, myocardial ischemia, and death. 3, 4 Fetal/neonatal effects include increased fetal heart rate and neonatal hypoglycemia. 3, 4

Preferred First-Line Tocolytic Agents

Nifedipine and indomethacin are the recommended first-line tocolytics for delaying delivery 48-72 hours in women with preterm labor and intact membranes after 26 weeks of gestation. 1, 2 These agents allow time for:

• Administration of antenatal corticosteroids 1, 2
• Maternal transfer to tertiary care facilities with appropriate NICU capabilities 1, 2

When Terbutaline May Be Considered

Terbutaline can be used as an alternative short-term tocolytic when:

• First-line agents (nifedipine/indomethacin) are contraindicated or unavailable 5
• Treatment duration will not exceed 48-72 hours 3, 4
• The goal is rapid cessation of contractions to facilitate discharge from triage 6

Dosing Recommendations

Subcutaneous terbutaline: 0.25 mg as a single dose has been shown to stop contractions and shorten triage stay (mean 4.1 hours vs 6.0 hours with hydration). 6 This approach does not improve pregnancy outcomes but facilitates faster discharge. 6

Intravenous terbutaline: Can be used for acute tocolysis but must be limited to 48-72 hours maximum. 3, 4

What Does NOT Work

Oral terbutaline for maintenance therapy is ineffective. After successful IV tocolysis, oral terbutaline does not reduce preterm birth rates, prolong pregnancy, or improve neonatal outcomes compared to no oral therapy. 7 Despite this, the subcutaneous pump delivery showed some benefit in retrospective studies, though this contradicts FDA warnings against prolonged use. 8

Clinical Algorithm for Tocolytic Selection

Step 1: Confirm preterm labor diagnosis

• Regular uterine contractions with cervical change 1
• Gestational age 24-34 weeks 1, 9
• Intact membranes (if ruptured, different management applies) 1

Step 2: Choose first-line tocolytic

• Preferred: Nifedipine or indomethacin 1, 2
• Alternative: Terbutaline (if first-line contraindicated) 5
• Duration: Maximum 48-72 hours only 1, 9, 3, 4

Step 3: Concurrent interventions

• Administer antenatal corticosteroids (24-34 weeks) 1
• Give magnesium sulfate for neuroprotection if <32 weeks 1, 9
• Arrange transfer to tertiary facility if needed 1, 9

Step 4: Antibiotics (only for specific indications)

• Give antibiotics: For preterm prelabor rupture of membranes (PPROM) ≥24 weeks 1
• Do NOT give antibiotics: For preterm labor with intact membranes (no benefit, potential harm) 5

Factors Affecting Terbutaline Success

In singleton pregnancies, terbutaline success (delaying delivery ≥48 hours) is significantly reduced by:

• Cervical dilation (OR 0.37; 95% CI 0.18-0.79) 10
• Cervical effacement (OR 0.36; 95% CI 0.17-0.75) 10

The overall success rate for delaying delivery ≥48 hours is approximately 83.4%. 10

Common Side Effects and Monitoring

Most common side effect: Tachycardia (95.1% of patients) 10

Monitor for: Maternal pulse (target >100 bpm if using oral dosing), blood glucose, potassium levels, and cardiac symptoms. 7, 10 Despite high rates of tachycardia, serious cardiovascular events are rare when used short-term. 10

Special Populations: Skeletal Dysplasia

In women with skeletal dysplasia, adjust fluid volumes proportionate to patient stature to avoid fluid overload, particularly when using terbutaline which has antidiuretic effects. 5 Standard preloading volumes (1L before epidural) should be reduced based on patient size. 5

Critical Clinical Pitfalls to Avoid

Never use terbutaline for:

• Maintenance therapy beyond 48-72 hours 3, 4
• Outpatient or home-based tocolysis 3, 4
• Routine oral maintenance after IV tocolysis (ineffective) 7

Never combine:

• Short-acting nifedipine with magnesium sulfate (causes uncontrolled hypotension and fetal compromise) 1

Remember: The primary goal of tocolysis is gaining 48-72 hours for corticosteroid administration and maternal transfer, NOT preventing preterm birth itself. 1, 9 No tocolytic, including terbutaline, has been consistently shown to improve perinatal mortality or long-term neonatal outcomes. 9

Neonatal Outcomes with Terbutaline Use

When terbutaline successfully delays delivery, neonatal outcomes include: mean birth weight 2294 ± 638g, respiratory distress syndrome 16.2%, intraventricular hemorrhage 1.4%, necrotizing enterocolitis 0.7%, sepsis 5.3%, and neonatal death 0.9%. 10