Medically reviewed on February 20, 2018.
Preterm labor occurs when regular contractions result in the opening of your cervix after week 20 and before week 37 of pregnancy.
Preterm labor can result in premature birth. 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.
The specific cause of preterm labor often isn't clear. Certain risk factors might increase the risk, but preterm labor can also occur in pregnant women with no known risk factors. Understand the signs and symptoms of preterm labor and next steps.
Signs and symptoms of preterm labor include:
- Regular or frequent sensations of abdominal tightening (contractions)
- Constant low, dull backache
- A sensation of pelvic or lower abdominal pressure
- Mild abdominal cramps
- Vaginal spotting or light bleeding
- Preterm rupture of membranes — in a gush or a continuous trickle of fluid after the membrane around the baby breaks or tears
- A change in type of vaginal discharge — watery, mucus-like or bloody
When to see a doctor
If you experience these signs or symptoms or you're concerned about what you're feeling, 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.
Preterm labor can affect any pregnancy. Many factors have been associated with an increased 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
- Problems with the uterus, cervix or placenta
- Smoking cigarettes or using illicit drugs
- Certain infections, particularly of the amniotic fluid and lower genital tract
- Some chronic conditions, such as high blood pressure and diabetes
- Stressful life events, such as the death of a loved one
- Too much amniotic fluid (polyhydramnios)
- Vaginal bleeding during pregnancy
- Presence of a fetal birth defect
- An interval of less than six months between pregnancies
- Infection of tissues that surround and support your teeth (periodontal disease)
Complications of preterm labor include delivering a preterm baby. This can pose a number of health concerns for your baby, 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.
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. 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.
- Eat a healthy diet. Some research suggests that a diet high in polyunsaturated fats (PUFAs) is associated with a lower risk of premature birth. PUFAs are found in nuts, seeds, fish and seed oils.
- Avoid risky substances. If you smoke, quit. Ask your health care provider about a smoking cessation program. Illicit drugs are off-limits, too.
- 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 starting during your second trimester and continuing until week 37 of pregnancy. In addition, your health care provider might offer progesterone, which is inserted in the vagina, as a preventive measure against preterm birth. If you are diagnosed with a short cervix before week 24 of pregnancy, your health care provider might also recommend use of progesterone until week 37 of pregnancy.
- 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.
Your health care provider will review your medical history and risk factors for preterm labor and evaluate your signs and symptoms. If you're experiencing regular uterine contractions and your cervix has begun to soften, thin and open (dilate) 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. If your water hasn't broken and there's no concern that the placenta is covering the cervix (placenta previa), he or she might also do a pelvic exam to determine whether your cervix has begun to open. Your health care provider might also check for uterine bleeding.
- Ultrasound. A transvaginal ultrasound might be used to measure the length of your cervix. An ultrasound might also be done to check for problems with the baby or placenta, confirm the baby's position, assess the volume of amniotic fluid, and estimate the baby's weight.
- Uterine monitoring. Your health care provider might use a uterine monitor to measure the duration and spacing of your contractions.
- 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. These results will be reviewed in combination with other risk factors. You'll also provide a urine sample, which will be tested for the presence of certain bacteria.
Once you're in labor, there are no medications or surgical procedures to stop labor. However, your doctor might recommend the following medications:
- Corticosteroids. If you're between weeks 24 and 34, your health care provider might recommend an injection of potent steroids to speed your baby's lung maturity. Corticosteroids might also be recommended starting at week 23 of pregnancy if you're at risk of delivering within seven days. In addition, corticosteroids might be recommended if you're between weeks 34 and 36 and six days of pregnancy, at risk of delivering within seven days and you haven't previously received them. You might be given a repeat course of corticosteroids if you're less than 34 weeks pregnant, at risk of delivering within seven days and a prior course of corticosteroids was given to you more than 14 days previously.
- Magnesium sulfate. Your doctor might offer magnesium sulfate if you have a high risk of delivering between weeks 24 and 32 of pregnancy. Some research has shown that it might reduce the risk of a specific type of damage to the brain (cerebral palsy) for babies born before 32 weeks of gestation.
- Tocolytics. Your health care provider might give you a medication called a tocolytic to temporarily stop your contractions. These medications won't halt preterm labor for longer than two 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. Your health care provider won't recommend a tocolytic if you have certain conditions, such as pregnancy-induced high blood pressure.
If you're not hospitalized, you might need to schedule weekly or more-frequent visits with your health care provider so that he or she can monitor signs and symptoms of preterm labor.
For some women, a surgical procedure known as cervical cerclage can help women who develop preterm labor because of a short cervix. During this procedure, the cervix is stitched closed with strong sutures. Typically, the sutures are removed after 36 completed weeks 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 or that your cervical length is less than 25 millimeters.
Lifestyle and home remedies
Preterm contractions might be Braxton Hicks contractions, which are common and don't necessarily mean that your cervix will begin to open. If you're having contractions that you think might be a symptom of preterm labor, try walking, resting or changing positions. This might stop false labor contractions. If you're in true preterm labor, however, your contractions will continue.
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. Consult your health care provider about healthy ways to relax and stay calm.
Preparing for an 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?
- What can I do — if anything — to help prolong my pregnancy?
- Are there any treatments that could help the baby?
- 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 or transportation?
Preterm labor poses serious risks for your baby. Work with your health care provider to understand your diagnosis and improve your chance of a healthy outcome.