Mayo Clinic Health Library

Preterm labor

Updated: 02-24-2012

Definition

A full-term pregnancy lasts about 40 weeks. Preterm labor occurs when contractions begin to open your cervix before 37 weeks of pregnancy.

If preterm labor can't be stopped, your baby will be born early. The earlier premature birth happens, the greater the health risks for your baby. Many premature babies (preemies) need special care in the neonatal intensive care unit. Preemies can also have long-term mental and physical disabilities. In addition, giving birth prematurely increases your risk of preterm labor in future pregnancies.

While the specific cause of preterm labor often isn't clear, certain risk factors can increase the risk of preterm labor. Find out if you're at risk of preterm labor and what you can do to prevent it.

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Symptoms

For some women, the signs and symptoms of preterm labor are unmistakable. For others, they're more subtle. During pregnancy, be on the lookout for:

  • Regular or frequent contractions — a tightening sensation in the abdomen
  • Constant low, dull backache
  • A sensation of pelvic or lower abdominal pressure
  • Mild abdominal cramps
  • Diarrhea
  • Vaginal spotting or bleeding
  • Watery vaginal discharge (water breaking) — in a gush or a trickle
  • A change in vaginal discharge

If you're concerned about what you're feeling — especially if you have vaginal bleeding accompanied by abdominal cramps or pain — contact your health care provider right away. Don't worry about mistaking false labor for the real thing. Everyone will be pleased if it's a false alarm.

Research doesn't support the benefits of home uterine monitoring as a routine practice, but it's sometimes recommended as a precaution. If your health care provider asks you to monitor yourself for contractions, lie on your side and place your fingertips on your lower abdomen. If you feel a firm tightening over the surface of your uterus, you might be having contractions. If you feel contractions, monitor yourself for an hour. Record when each contraction starts, how long it lasts and how many you have in an hour. While some uterine activity before 37 weeks of pregnancy is normal, contact your health care provider if you have four contractions every 20 minutes or eight contractions in an hour.

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Risk factors

Preterm labor can affect any pregnancy and many women who have preterm labor have no known risk factors. Many factors can increase the risk of preterm labor, however, including:

  • Previous preterm labor or premature birth, particularly in the most recent pregnancy or in more than one previous pregnancy
  • Pregnancy with twins, triplets or other multiples
  • Certain problems with the uterus, cervix or placenta
  • Smoking cigarettes, drinking alcohol or using illicit drugs
  • Certain infections, particularly of the genital tract
  • Some chronic conditions, such as high blood pressure and diabetes
  • Being underweight or overweight before pregnancy, or gaining too little or too much weight during pregnancy
  • Stressful life events, such as the death of a loved one
  • Domestic violence or any form of abuse during pregnancy
  • Multiple miscarriages
  • Red blood cell deficiency (anemia), particularly during early pregnancy
  • Too much amniotic fluid (polyhydramnios)
  • Pregnancy complications, such as preeclampsia
  • Vaginal bleeding during pregnancy
  • Presence of a fetal birth defect
  • Little or no prenatal care
  • An interval of less than six months since the last pregnancy

Also, having a short cervical length or the presence of fetal fibronectin — a substance that acts like a glue between the fetal sac and the lining of the uterus — in your vaginal discharge might be linked to an increased risk of preterm labor. If you have risk factors for preterm labor, your health care provider might use ultrasounds to measure the length of your cervix at prenatal appointments.

While some research suggests that gum disease might be linked with premature birth, treatment of periodontal disease during pregnancy hasn't been proved to reduce the risk of premature birth.

If you're at risk of preterm labor or premature birth, you might be referred to a specialist.

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Complications

Many women treated for preterm labor deliver at or near term. Sometimes, however, preterm labor can't be stopped — or an infection or other complications make an early delivery safer for mother or baby.

If preterm labor can't be stopped, your baby will be born prematurely. This could pose various health concerns, such as low birth weight, breathing difficulties, underdeveloped organs and vision problems. Children who are born prematurely also have a higher risk of learning disabilities and behavioral problems. The risks are greatest for babies born before 32 weeks of pregnancy.

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Preparing for your appointment

If you develop any signs or symptoms of preterm labor, contact your health care provider right away. Depending on the circumstances, you might need immediate medical care.

Here's some information to help you get ready for your appointment, as well as what to expect from your health care provider.

What you can do
Before your appointment, you might want to:

  • Ask about pre-appointment restrictions. In most cases you'll be seen immediately. If that's not the case, ask whether you should restrict your activity while you wait for your appointment.
  • Ask a loved one or friend to join you for your appointment. The fear you might be feeling about the possibility of preterm labor can make it difficult to focus on what your health care provider says. Take someone along who can help remember all the information.
  • Write down questions to ask your health care provider. That way, you won't forget anything important that you want to ask, and you can make the most of your time with your health care provider.

Below are some basic questions to ask your health care provider about preterm labor. If any additional questions occur to you during your visit, don't hesitate to ask.

  • Am I in labor?
  • Is my baby at risk of being born prematurely?
  • Is there anything I can do to help prolong my pregnancy?
  • Are there any treatments that could help the baby?
  • Do I need to be on bed rest? If so, for how long? What kinds of activities will I still be able to do? Will I need to be in the hospital?
  • What signs or symptoms should prompt me to call you?
  • What signs or symptoms should prompt me to go to the hospital?
  • What are the risks if my baby is born now?

What to expect from your health care provider
Your health care provider is likely to ask you a number of questions, including:

  • When did you first notice your signs or symptoms?
  • Are you having contractions? If so, how many an hour?
  • Have you had any changes in vaginal discharge or bleeding?
  • Have you been exposed to an infectious disease? Do you have a fever?
  • Have you had any previous pregnancies, miscarriages, or cervical or uterine surgeries that I'm not aware of?
  • Do you or did you smoke? How much?
  • How far do you live from the hospital?
  • How long would it take you to get to the hospital in an emergency, including time to arrange any necessary child care, transportation and so on?
  • Do you have friends or loved ones nearby who could care for you if you need bed rest?
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Tests and diagnosis

To help diagnose preterm labor, your health care provider will document your signs and symptoms. If you're experiencing regular, painful contractions and your cervix has begun to soften, thin and open before 37 weeks of pregnancy, you'll likely be diagnosed with preterm labor.

Tests and procedures to diagnose preterm labor include:

  • Pelvic exam. Your health care provider might evaluate the firmness and tenderness of your uterus and the baby's size and position. He or she might also do a pelvic exam to determine if your cervix has begun to open — if your water hasn't broken and the placenta isn't covering your cervix (placenta previa).
  • Ultrasound. An ultrasound might be used to measure the length of your cervix and determine your baby's size, age, weight and position in your uterus. You might need to be monitored for a period of time and then have another ultrasound to measure any changes in your cervix.
  • Uterine monitoring. Your health care provider might use a uterine monitor to measure the duration and spacing of your contractions.
  • Fetal monitoring. Your health care provider might use a fetal heart rate monitor to record your baby's heartbeat and check on his or her well-being.
  • Lab tests. Your health care provider might take a swab of your vaginal secretions to check for the presence of certain infections and fetal fibronectin — a substance that acts like a glue between the fetal sac and the lining of the uterus and is discharged during labor.
  • Maturity amniocentesis. If you're at least 32 weeks pregnant, your health care provider might recommend a procedure in which amniotic fluid is removed from the uterus (amniocentesis) to determine your baby's lung maturity. The technique can also be used to detect an infection in the amniotic fluid.

If you're in preterm labor, your health care provider will explain the risks and benefits of trying to stop your labor. Keep in mind that preterm labor sometimes stops on its own.

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Treatments and drugs

For some women, a surgical procedure known as cervical cerclage can help prevent premature birth. During this procedure, the cervix is stitched closed with strong sutures. Typically, the sutures are removed when the baby is considered full term — during week 37 of pregnancy. If necessary, the sutures can be removed earlier. Cervical cerclage might be recommended if you're less than 24 weeks pregnant, you have a history of early premature birth and an ultrasound shows that your cervix is opening. However, cervical cerclage isn't recommended if you're in active preterm labor.

If you're less than 34 weeks pregnant and in active preterm labor, your health care provider might recommend hospitalization. In addition, your health care provider might give you medications to temporarily halt preterm labor or promote your baby's readiness for birth, including:

  • Corticosteroids. If you're between weeks 24 and 34, your health care provider might recommend an injection of potent steroids in the form of betamethasone (Celestone) or dexamethasone to speed your baby's lung maturity. After week 34, your baby's lungs might be mature enough for delivery without steroids.
  • Tocolytics. Your health care provider might give you a medication called a tocolytic to temporarily stop your contractions. Tocolytics, which can be given orally or as injections, aren't likely to halt preterm labor for longer than two to seven days because they don't address the underlying cause of preterm labor. However, they might delay preterm labor long enough for corticosteroids to provide the maximum benefit or, if necessary, for you to be transported to a facility that can provide specialized care for your premature baby. If one type of tocolytic doesn't stop preterm labor, you might be given another type. Different tocolytics can cause different side effects for you and your baby. Your health care provider can help you weigh the risks and benefits. In addition, your health care provider won't recommend a tocolytic if you have certain conditions, such as a specific problem with your placenta.

If you're not hospitalized, you might need to schedule weekly visits with your health care provider so he or she can monitor signs and symptoms of preterm labor.

Aside from starting too early, preterm labor typically resembles normal labor. If relaxation and breathing techniques aren't enough to control the pain, ask for relief. Your health care provider might recommend an epidural block, a spinal block or other options.

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Lifestyle and home remedies

If you're having contractions that you think might be a symptom of preterm labor, try walking, resting or changing your position. This might halt false labor contractions. If you're in true preterm labor, however, your contractions will continue. Keep in mind that preterm contractions are common and don't necessarily mean that your cervix will begin to open.

Sometimes bed rest and drinking fluids are recommended, but neither is a proven remedy for halting preterm labor or preventing premature birth.

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Coping and support

If you're at risk of preterm labor or premature birth, you might feel scared or anxious about your pregnancy. This might be especially true if you have a history of preterm labor or premature birth. You might be reluctant to think about the future and constantly be on the lookout for signs and symptoms of preterm labor. In addition, prenatal visits might make you particularly nervous — for fear that you'll hear bad news.

Unfortunately, anxiety can affect your health and your baby's health. Consult your health care provider about healthy ways to relax and stay calm. Some studies suggest that certain techniques — such as imagining pleasant objects or experiences or listening to music — can reduce anxiety during pregnancy.

If you give birth prematurely, it won't affect your physical recovery from childbirth. However, the common stresses after delivery could be magnified by your baby's condition. Preemies often need intensive medical care after birth, sometimes requiring lengthy hospital stays. You might be worried about the possible long-term effects for your baby. As the parent of a premature newborn, you might feel that you did something to cause the premature birth or that you could have done more to prevent it. Try to let go of any feelings of guilt about your baby's premature birth by talking about them with your baby's care providers, your partner and other loved ones. Focus your energy on caring for and getting to know your child.

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Prevention

You might not be able to prevent preterm labor — but there's much you can do to promote a healthy, full-term pregnancy. For example:

  • Seek regular prenatal care. Prenatal visits can help your health care provider monitor your health and your baby's health. Mention any signs or symptoms that concern you, even if they seem silly or unimportant. If you have a history of preterm labor or develop signs or symptoms of preterm labor, you might need to see your health care provider more often during pregnancy for exams and tests.
  • Eat a healthy diet. During pregnancy, you'll need more folic acid, calcium, iron and other essential nutrients. A daily prenatal vitamin — ideally starting a few months before conception — can help fill any gaps.
  • Gain weight wisely. Gaining the right amount of weight can support your baby's health — and make it easier to shed the extra pounds after delivery. A weight gain of 25 to 35 pounds (about 11 to 16 kilograms) is often recommended for women who have a healthy weight before pregnancy. If you're overweight before you conceive, you might need to gain less weight. If you're carrying twins or triplets, you might need to gain more weight. Work with your health care provider to determine what's right for you.
  • Avoid risky substances. If you smoke, quit. Smoking might trigger preterm labor. Alcohol and illicit drugs are off-limits, too. In addition, medications of any type — even those available over-the-counter — deserve caution. Get your health care provider's OK before taking any medications or supplements.
  • Consider pregnancy spacing. Some research suggests a link between pregnancies spaced less than six months apart and an increased risk of premature birth. Consider talking to your health care provider about pregnancy spacing.
  • Be cautious when using assisted reproductive technology (ART). If you're planning to use ART to get pregnant, consider how many embryos will be implanted. Multiple pregnancies carry a higher risk of preterm labor.

If your health care provider determines that you're at increased risk of preterm labor, he or she might recommend taking additional steps to reduce your risk, such as:

  • Taking preventive medications. If you have a history of premature birth, your health care provider might suggest weekly shots of a form of the hormone progesterone called hydroxyprogesterone caproate (Makena) during your second trimester. In addition, new research shows that treatment with a vaginal progesterone gel during the second and third trimesters might decrease the risk of premature birth in women who have short cervixes.
  • Restricting sexual activity. If you have a history of preterm labor or experience signs or symptoms of preterm labor, you might need to restrict sexual activity and monitor yourself for contractions after sex.
  • Limiting certain physical activities. If you're at risk of preterm labor or develop signs or symptoms of preterm labor, your health care provider might suggest avoiding heavy lifting or spending too much time on your feet. Sometimes it makes sense to scale back other physical activities, such as certain exercises and travel, too.
  • Managing chronic conditions. Certain conditions, such as diabetes and high blood pressure, increase the risk of preterm labor. Work with your health care provider to keep any chronic conditions under control.

If you have a history of preterm labor or premature birth, you're at risk of a subsequent preterm labor. Work with your health care provider to manage any risk factors and respond to early warning signs and symptoms.

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