Preterm Labour
Medications
If your contractions are causing changes in your cervix (preterm labour), or you have signs of infection or preterm premature rupture of membranes (pPROM), you may be treated with one or more medications, including:
- Antibiotics, to prevent or treat infection. Antibiotic treatment does not always eliminate infection. But it is often effective in preventing infection when the amniotic sac has ruptured (pPROM) and risk of infection is high.16 Antibiotics can also delay delivery after pPROM.3
- Medications (antenatal corticosteroids) to speed up fetal lung development if birth is anticipated between the 24th and 34th weeks of pregnancy.
- Tocolytic medications, to slow down contractions and try to delay labour.
Tocolytic treatment is more likely to be successful when preterm labour is recognized and treated right away, before membranes have ruptured or the cervix has effaced and dilated beyond 4 cm.1 Delaying labour even for a short time can allow you to be:
- Transported to a medical centre that has a neonatal intensive care unit (NICU).
- Given antenatal corticosteroids, which take a minimum of 48 hours to fully benefit a fetus's lungs. However, 24 hours does provide some benefit.
Medication Choices
Antibiotic medication is chosen by your doctor based on the type of infection suspected.
Antenatal corticosteroids (betamethasone or dexamethasone) help prepare the fetus's lungs for preterm birth.
Tocolytic medications that are used to stop preterm labour include:
What To Think About
A single course of antenatal corticosteroid treatment, used to prepare the fetus's lungs for birth, is considered to be the least risky, most effective treatment available for avoiding the most common preterm fetal complications at birth.2 It is standard procedure to give corticosteroid injections to most women before preterm birth for pregnancies at 24 to 34 weeks of gestation.
If you test positive for infection, you will be treated with an antibiotic during pregnancy or labour in an attempt to prevent infection in your newborn. This is why women with preterm labour are screened for group B strep (GBS).
Antibiotic treatment for preterm labour is:
- Beneficial for women with pPROM. Antibiotics may delay labour and reduce risk of newborn infection.3
- Not recommended for women with intact membranes and no evidence of infection.17
- Continued for 5 days in women with GBS.
- Used for women whose GBS diagnosis is unknown.
Tocolytic medications are used to delay preterm birth so that antenatal corticosteroids can work. Tocolytics cause side effects that may require stopping treatment or trying a different tocolytic medication. Side effects are closely monitored and rarely cause permanent damage to the mother or fetus but can be unpleasant for the mother (see the specific medications). During tocolytic treatment, a woman is usually on continuous fetal monitoring and her vital signs are checked frequently.
Considerations before using tocolytics include your and your fetus's health, how far your labour has progressed, whether your membranes have ruptured, and whether you have an infection. Certain tocolytic medications can be dangerous when a fetus is showing signs of distress or for women with certain health conditions (such as heart problems, severe pre-eclampsia, or poorly controlled diabetes or high blood pressure).
Tocolytics aren't likely to work at all after membranes have ruptured or the cervix is well-effaced and dilated at or beyond 4 cm.1
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| Author: | Kathe Gallagher, MSW Carrie Henley | Last Updated: April 10, 2007 |
| Medical Review: | Joy Melnikow, MD, MPH - Family Medicine Anne C. Poinier, MD - Internal Medicine Gregory A L Davies, MD, FRCSC, FACOG - Maternal-Fetal Medicine William Gilbert, MD - Perinatology | |
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