If you are having preterm labor, you may be given medication. Drugs for preterm labor fall into four categories:

  1. Tocolytics —to slow or stop preterm labor contractions
    1. Calcium channel blockers
    2. Prostaglandin synthetase inhibitors (cyclooxygenase inhibitors)
    3. Oxytocin receptor agonist
    4. Betamimetics
    5. Magnesium sulfate
  2. Corticosteroids —to help the baby’s lungs and brain mature
  3. Antibiotics —to prevent infection in the mother and baby
  4. Progesterone —given before preterm labor, as a preventive measure


Tocolytics are drugs that minimize the strength and number of contractions. Although an ideal goal would be to stop preterm labor, the most that can be reasonably expected from current tocolytics is a delay of 48 hours. This delay allows time for treatment with steroids and antibiotics. Steroids are given to speed the baby’s lung development. Even a few extra days in the womb can be vital to the baby’s development. Antibiotics may be given to treat infection (in such a case, the infection is suspected rather than established). During this time, you may also be transferred to a better-equipped hospital.

These drugs can be given through an IV or by mouth between 24 and 34 weeks gestation.

Good Evidence of Benefit

Calcium Channel Blockers

  • Common name: Nifedipine (Adalat, Procardia)

Calcium channel blockers reduce smooth muscle contractions, such as those in the uterus. In addition, statistically significant benefit has been seen for infants in terms of respiratory distress syndrome , necrotizing enterocolitis , intraventricular hemorrhage, and jaundice .

No Persuasive Evidence of Benefit

Prostaglandin Synthetase Inhibitors (Cyclooxygenase Inhibitors)

Common names include:

  • Ibuprofen (Advil, Motrin)
  • Indomethacin (Indocin
  • Ketorolac (Toradol)
  • Sulindac (Clinoril)

Prostaglandins cause uterine contractions, so these drugs are meant to block the production of prostaglandin.

Oxytocin Receptor Agonist

  • Common name: Atisoban

Oxytocin receptor agonist does not have evidence of benefit for preventing preterm birth and may have harmful effects.

No Evidence of Benefit and May Have Harmful Effects


Common names include:

  • Terbutaline (Brethaire, Brethine, Bricanyl)
  • Ritodrine (Yutopar)

These drugs cause uterine muscles to relax.

Magnesium Sulfate

This is a muscle relaxant that is given intravenously.


Common names include:

  • Betamethasone (Betatrex, Diprolene, Maxivate)
  • Dexamethasone (Decadron, Dexameth, Dexone, Hexadrol)

If you are between 24 and 34 weeks of pregnancy, your doctor may give corticosteroids. These drugs help your baby’s lungs mature. They also reduce the risk of respiratory distress syndrome and bleeding in the brain. With these drugs, your baby will breathe easier after delivery. The benefits of corticosteroids are seen in 24 hours and last up to seven days after treatment.


Common names include:

  • Penicillin
  • Ampicillin
  • Clindamycin
  • Erythromycin
  • Amoxicillin

Antibiotics help treat infection in both the mother and the baby. Preterm babies are at increased risk of infection because their immune systems are immature.


Common names for progesterone injection include:

  • 17-HPC
  • 17 Alpha-hydroxyprogesterone Caproate
  • 17 A-hydroxyprogesterone Caproate
  • Delalutin (off-market)
  • Gestiva (Adeza)

Common names for progesterone vaginal gel include:

  • Crinone (Serono/Columbia)
  • Procheive (Columbia)

After an ultrasound has ruled out multiple births and major fetal anomalies, progesterone therapy can be given between 16 to 23 weeks gestation to prevent preterm labor and delivery. This treatment, which is a type of hormone therapy, is given if you have a past history of preterm birth (before 37 weeks gestation).

Researchers have found positive results (a reduction in preterm deliveries) with this form of therapy for a specific group of women—those who are pregnant with a single fetus and who have a history of preterm birth. Studies are needed to further investigate progesterone’s long-term effects, for example, whether increasing gestation leads to improved infant health over time, as well as what the medication’s safety issues are for both the mother and the infant.