Reference — Maternal-Newborn
Tocolytic Medications Reference
Four agents, one shared purpose: roughly 48 hours of delay so corticosteroids, magnesium neuroprotection, and transfer can happen. Just as important is the list at the bottom — when stopping labor is the wrong move.
Educational use only. Agent selection, dosing, and hold parameters follow provider orders and facility protocols — this reference covers drug characteristics for learning. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
Agents at a Glance
| Drug | Class | Monitoring | Notes |
|---|---|---|---|
| Nifedipine | Calcium channel blocker | Maternal BP and heart rate — hypotension is the main concern; avoid combining with IV magnesium per provider judgment | Oral dosing; commonly first-line in many protocols |
| Indomethacin | NSAID (prostaglandin synthesis inhibitor) | Amniotic fluid (oligohydramnios) and fetal ductus arteriosus with longer use | Generally limited to <32 weeks and ≤48-hour courses for exactly those fetal reasons |
| Magnesium sulfate | Smooth-muscle relaxant (mechanism debated) | DTRs, respiratory rate, urine output — the standard magnesium trio; calcium gluconate at the bedside | Where used, often overlaps its neuroprotection role before ~32 weeks |
| Terbutaline | Beta-2 agonist | Maternal heart rate (tachycardia, palpitations), glucose, potassium; fetal tachycardia | Short-term/acute use only — boxed warning against prolonged use; hold per protocol for maternal HR thresholds |
When Tocolysis Is Contraindicated
• Intrauterine infection (chorioamnionitis)
• Significant abruption or hemorrhage
• Severe preeclampsia / eclampsia
• Fetal demise or lethal anomaly
• Non-reassuring fetal status
• Advanced labor (membrane rupture with advanced dilation shifts the goal to safe delivery)
The shared logic: when the intrauterine environment is the threat — infection, bleeding, a failing placenta — delaying delivery protects nothing.
What the 48 Hours Buys
• Betamethasone — two IM doses 24 hours apart; lung-maturity benefit builds over 24–48 hours
• Magnesium neuroprotection before ~32 weeks
• GBS prophylaxis addressed before delivery
• Maternal transfer to a facility with the right NICU level — transporting the fetus in utero beats any ambulance isolette
Related Resources
Standards & sources
Fact-checked Jun 20, 2026This page is written to align with American College of Obstetricians and Gynecologists (ACOG) · AWHONN · American Academy of Pediatrics (AAP) — newborn. It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →