Your doctor may be helping you take precautions to avoid a preterm birth. The longer your baby can develop in the womb, the less likely they’ll have problems associated with preterm birth.

Preterm birth can result in issues with the lungs, heart, brain, and other body systems of a newborn baby. However, the good news is that advances in the study of preterm labor have identified effective drugs that may delay delivery.

If you’re having signs of premature labor, call a doctor immediately.

Symptoms of preterm labor include:

  • frequent or consistent contractions (tightening in your belly)
  • low back pain that is dull and constant
  • pressure in your pelvis or lower abdominal area
  • mild cramps in your abdomen
  • water breaking (watery vaginal discharge in a trickle or a gush)
  • a change in vaginal discharge
  • spotting or bleeding from your vagina
  • diarrhea

Medications and therapies for preterm labor

If you’re less than 37 weeks pregnant when you experience preterm labor symptoms, your doctor may try to prevent delivery by offering certain medications.

In addition to giving tocolytic medicines to prevent contractions, your doctor may prescribe steroids to improve the baby’s lung function.

If your water has broken, you may also be given antibiotics to prevent infection and help you stay pregnant longer.

If you are at high risk for preterm labor, your doctor may suggest the hormone progesterone.

Read on to learn more about these different preterm labor therapies.

Some people go into labor very early. If you deliver before 34 weeks, receiving corticosteroid injections can improve your baby’s chances of doing well. These help the baby’s lungs to function.

Steroids are usually injected into one of the large muscles (arms, legs, or buttocks) of the pregnant person. The injections are given two to four times over a 2-day period, depending on which steroid is used.

The most common steroid, betamethasone (Celestone), is given in two doses, 12 milligrams (mg) each, 12 or 24 hours apart. The medications are most effective from 2 to 7 days after the first dose.

Corticosteroids aren’t the same as the bodybuilding steroids used by athletes.

Studies have shown that corticosteroids are important and widely used interventions. There is little scientific support that they cause increased risks.

What are the benefits of steroids?

Steroid treatment reduces the risk of lung problems for babies who are born early, particularly for those born between 29 and 34 weeks of pregnancy.

A 2016 study on mice showed that steroid treatments can reduce the risk of bronchopulmonary dysplasia, a condition that can lead to chronic lung disease in babies. A 2020 study showed that early treatment is important to maximize benefits.

Steroids may also reduce other complications in babies. A 2017 review of studies showed that some babies have fewer problems with their intestines and with bleeding in the brain when their pregnant parent received a course of betamethasone prior to birth.

If you’re admitted to a hospital in preterm labor or you have a medical problem that your doctors worry will require an early delivery, you’ll probably be offered a course of steroids.

Staying pregnant for those first 2 days after a corticosteroid shot is the first major milestone for you and your baby (or babies).

What are the risks of taking steroids?

Older data has not shown any significant risks associated with a single course of steroids.

A 2017 review of studies showed a small increase in the risk of a cleft lip with first trimester corticosteroid use. Use of steroids this early in the pregnancy is not common.

A 2019 study indicated a link between corticosteroid use and low birth weight, but research is still ongoing.

One 2019 data review found that of repeat prenatal corticosteroids given to pregnant people with ongoing risks of preterm labor can reduce the likelihood of baby needing respiratory support at birth.

However, repeat courses were also associated with lower birth weight, length, and head circumference.

Currently, repeated courses aren’t recommended, unless you’re participating in a research study.

Who should take steroids?

The American College of Obstetricians and Gynecologists (ACOG) reaffirmed their recommendations in 2020 for when steroids should be used:

  • A single course is recommended when the pregnant parent is at risk for preterm delivery between 24 and 34 weeks of pregnancy.
  • A single course is recommended between 34 and 37 weeks for those at risk of preterm birth within 7 days, and who have not already received a course.
  • A single repeat course of corticosteroids can be considered for those at risk of preterm delivery within 7 days, whose prior course was given more than 14 days prior.

Who shouldn’t take steroids?

Steroids may make diabetes (both long-standing and pregnancy-related) more difficult to control. When given in combination with a beta-mimetic drug (terbutaline, brand name Brethine), they can be even more problematic.

People with diabetes will require careful blood sugar monitoring for 3 to 4 days after receiving steroids.

In addition, those with active or suspected infection in the womb (chorioamnionitis) shouldn’t receive steroids.

Some pregnant people are more likely than others to go into labor early. Those at high risk of a preterm delivery include those who:

  • have already given birth to a preterm baby
  • are carrying more than one baby (twins, triplets, etc.)
  • got pregnant shortly after a previous pregnancy
  • use tobacco or alcohol, or misuse drugs
  • conceived through in vitro fertilization
  • have had more than one miscarriage or abortion
  • have other health issues (such as an infection, anatomical abnormalities in the uterus or cervix, or certain chronic conditions)
  • have nutritional deficiencies
  • experience a very stressful or traumatic event during pregnancy (physical or emotional)

It’s important to note that many pregnant people who experience symptoms of preterm labor have none of the known risk factors.

If you’ve had a preterm birth in the past, your obstetrician may recommend you get a progesterone shot or pessary (vaginal suppository). The most common form of progesterone hormone administered to prevent preterm birth is the 17-OHPC shot, or 17-alphahydroxyprogesterone caproate.

The 17-OHPC shot is a synthetic progesterone that is often administered prior to the 21st week of gestation. It’s intended to prolong pregnancy. The hormone works by keeping the uterus from contracting. The shot is typically given into the muscle on a weekly basis.

If progesterone is given as a pessary, it’s inserted into the vagina.

A prescription is required for this hormone treatment, and both the shots and the suppositories should be administered by a doctor.

What are the benefits of progesterone shots?

A 2013 review of clinical studies of 17-OHPC has demonstrated its ability to prolong pregnancy. Those at risk of delivering a baby before 37 weeks may be able to stay pregnant longer if they receive 17-OHPC prior to the completion of 21 weeks of pregnancy.

A 2003 study demonstrated that if preterm birth does occur, babies who survive have fewer complications if their parent received 17-OHPC before the birth.

What are the risks of progesterone shots?

As with any shot and hormone administration, 17-OHPC shots may cause some side effects. The most common include:

  • pain or swelling in the skin at the injection site
  • a skin reaction at the injection site
  • nausea
  • vomiting

Some experience other side effects such as:

  • mood swings
  • headaches
  • abdominal pain or bloating
  • diarrhea
  • constipation
  • changes in sexual drive or comfort
  • dizziness
  • allergy
  • flu-like symptoms

People who receive the pessary are more likely to have unpleasant discharge or irritation in their vagina.

There is no indication that 17-OHPC shots have any negative effect on miscarriage, stillbirth, preterm birth, or birth defect risk.

There isn’t enough known about the long-term effects on parents or babies to recommend shots for those with other predisposing factors for preterm birth.

Although 17-OHPC shots may reduce the risk of preterm birth and some of its complications, it doesn’t appear to reduce the risk of infant death.

A 2019 study contradicted earlier studies and found that the drug was not effective in preventing preterm birth. After the results were released, the ACOG made a statement recommending taking into account the collective body of evidence and using 17-OHPC primarily in very high risk situations.

Who should get 17-OHPC shots?

Pregnant people who’ve previously experienced preterm labor are often offered this hormone shot. The ACOG recommends that only those with a history of labor prior to 37 weeks’ gestation receive a 17-OHPC shot.

Who shouldn’t get 17-OHPC shots?

People without a prior preterm birth shouldn’t receive 17-OHPC shots until more research confirms their safety and effectiveness for other risk factors. In addition, those with allergies or serious reactions to the shot may wish to discontinue their use.

As well, there are some situations in which a longer pregnancy may be harmful. Preeclampsia, amnionitis, and lethal anomalies (or imminent fetal death) may make a prolonged pregnancy dangerous.

Always consult carefully with a health professional before deciding to receive 17-OHPC shots or suppositories.

Tocolytic medications are used to delay delivery 48 hours or more. Tocolytic drugs include the following medications:

  • terbutaline (although it’s no longer considered safe for injection)
  • ritodrine (Yutopar)
  • magnesium sulfate
  • calcium channel blockers
  • indomethacin (Indocin)

Tocolytics are prescription drugs that should only be administered between weeks 20 and 37 of pregnancy if symptoms of preterm labor exist. They shouldn’t be combined except under the close supervision of a doctor.

In general, tocolytic drugs only delay delivery. They don’t prevent complications of preterm birth, fetal death, or maternal problems associated with preterm labor. They’re often given with prenatal corticosteroids.

What are the benefits of tocolytics?

All tocolytics, but prostaglandin inhibitors in particular, are effective at delaying delivery between 48 hours and 7 days. This allows corticosteroids time to speed development of the baby.

Tocolytics themselves don’t decrease the chances of death or illness for the newborn. Instead, they merely give extra time for the baby to develop or for other drugs to work.

Tocolytics may also delay delivery long enough for the pregnant person to be transported to a facility with a neonatal intensive care unit if preterm birth or complications are likely.

What are the risks of tocolytics?

Tocolytics have a variety of side effects that range from very mild to very serious.

Common side effects include:

More serious side effects can include:

  • blood sugar changes
  • breathing difficulties
  • changes in blood pressure

Because certain tocolytic drugs carry different risks, the specific drug chosen should depend on health and personal risks.

There is some controversy over whether tocolytics themselves can cause problems at birth, such as breathing problems for the baby or infection in the pregnant parent, when the drug is given after membranes have ruptured.

Who should get tocolytics?

Pregnant people experiencing the symptoms of preterm labor, particularly before 32 weeks’ gestation, should be considered to receive tocolytic drugs.

Who shouldn’t get tocolytics?

According to ACOG, people shouldn’t get tocolytic drugs if they’ve experienced any of the following:

  • severe preeclampsia
  • placental abruption
  • infection of the uterus
  • lethal abnormalities
  • signs of imminent fetal death or delivery

In addition, each type of tocolytic drug has risks for people with certain conditions. For example, those with diabetes or thyroid problems shouldn’t receive ritodrine, and those with serious liver or kidney problems shouldn’t receive prostaglandin synthetase inhibitors.

A doctor should have a thorough understanding of all health problems before prescribing a specific tocolytic drug.

Antibiotics are routinely given to pregnant people in preterm labor when the bag of water surrounding the baby has broken. This is because ruptured membranes put a pregnant person and their baby at greater risk for infection.

In addition, antibiotics are frequently used to treat infections such as chorioamnionitis and group B streptococcus (GBS) during preterm labor. Antibiotics require a prescription and are available in pill form or intravenous solution.

What are the benefits of antibiotics?

Many large studies have shown that antibiotics reduce risks and prolong pregnancy after the water breaks early.

It’s possible that antibiotics may delay or prevent preterm birth by treating conditions (such as infections) that can cause preterm birth.

On the other hand, it’s unclear whether antibiotics can delay delivery for those who are in preterm labor but haven’t broken their water. For now, using antibiotics to help treat all preterm labor remains controversial.

There’s also data showing that antibiotics are helpful during preterm labor for people who carry the GBS bacteria. About 1 in 4 pregnant people will carry GBS, and babies who get infected during labor and delivery can become very sick.

Antibiotics can treat GBS and reduce complications of a subsequent infection in the newborn, but carry risks for the parent.

Most healthcare providers test for the GBS bacteria between weeks 36 and 38 of the pregnancy. The test involves taking swab samples from the lower vagina and rectum.

Because it can take a few days for test results to be returned, the general practice is to begin treating for GBS before confirmation of infection.

Ampicillin and penicillin are the antibiotics most commonly used for treatment.

What are the risks of antibiotics?

The primary risk of antibiotics during preterm labor is an allergic reaction. In addition, some babies may be born with an infection that has resistance to antibiotics, making treatment of postpartum infections in those babies more difficult.

Who should get antibiotics?

According to ACOG, only those with signs of infection or ruptured membranes (early water break) should receive antibiotics during premature labor. It isn’t currently recommended for routine use in people without either of these problems.

Who shouldn’t get antibiotics?

Those without signs of infection and with intact membranes should likely not receive antibiotics during preterm labor.

In addition, some may have allergic reactions to particular antibiotics. A person with known allergies to antibiotics should receive alternative antibiotics or none at all, following the recommendations of health professionals.