II. Indications
III. Contraindications (See specific medications)
- Intrauterine Fetal Demise or lethal fetal anomaly
-
Nonreassuring Fetal Status
- Fetal Bradycardia <100
- Fetal Tachycardia >180
- Severe Preeclampsia or Eclampsia
- Maternal bleeding with hemodynamic instability
- Maternal Systolic Blood Pressure <90 mmHg
- Maternal cardiopulmonary symptoms (e.g. Shortness of Breath, Chest Pain)
- Chorioamnionitis
IV. Preparations: Preferred Tocolytics
-
General Indications
- Stops labor for 24-48 hours
- Allows maternal transport and Corticosteroid doses
-
Magnesium Sulfate
- Load: 6 grams bolus IV over 20 min (Very high dose!, some protocols use 4 g load)
- Maintenance: 2 grams/hour IV infusion (max: 3 g/h)
- Must follow protocols for patient safety
- Tocolytic and neuroprotective (with decreased risk of Cerebral Palsy in deliveries before 32 weeks)
- Does not prevent preterm birth
-
Indomethacin (Indocin)
- Load: 50-100 mg orally or rectally
- Maintenance: 25-50 mg orally every 4-6 hours for up to 48 hours
- Avoid use >48 hours (risk of oligohydramnios, premature closure ductus arteriosus)
- Not recommended after 32 weeks due to ductus arteriosus constriction
-
Nifedipine (Procardia)
- Load: 30 mg orally
- Maintenance: 10-20 mg every 4-6 hours (max: 180 mg/day)
- Higher risk of maternal adverse effects when combined with Magnesium Sulfate
V. Preparations: Other Tocolytics
-
Terbutaline
- Load: 0.25 mg SQ every 20-30 min for up to 4 doses
- Maintenance: 0.25 mg every 3-4 hours until Uterus quiet for 24 hours
- Effective at temporarily stopping contractions
- Results in shortest hospital triage stays
- Guinn (1997) Am J Obstet Gynecol 177:814-87 [PubMed]
- Oral Terbutaline is not effective in Preterm Labor
-
Ritodrine
- Not available in the United States as of 2013
- Curiously, was the only FDA approved Preterm Labor Tocolytic
- Not shown to be more effective than Placebo
- (1992) N Engl J Med 327:308-12 [PubMed]