What Is Preterm Labor and Birth?
Preterm birth is any birth that occurs before the 37th week of pregnancy. It is the cause of many infant deaths and lingering infant illnesses in the United States. Every pregnant woman needs to know about preterm labor and birth—why it happens and what she can do to help prevent it.

Preterm birth occurs in about 11 percent of all pregnancies in the United States, often for reasons we just don't understand. A normal pregnancy should last about 40 weeks. That amount of time gives the baby the best chance to be healthy. A pregnancy that ends between 20 weeks and 37 weeks is considered preterm, and all preterm babies are at significant risk for health problems.

You might have read in the newspapers about babies who are born really early and do very well, but it's important for you to know that those babies are the exceptions. Babies who are born preterm are at a very high risk for brain and other neurological problems, breathing problems, digestive problems, and death in the first few days of life. Unfortunately, they also are at risk for problems later in their lives in the form of delayed development and learning problems in school, so the effects of preterm birth can be devastating throughout the child's life. The earlier in pregnancy a baby is born, the more health problems it is likely to have.

Why Does Preterm Labor Occur?
We're not really sure. There are many theories, but none of them has been proven. Stress might play a part for some women, personal health history or infection for others, or activities in pregnancy such as smoking or drug use for others.

Who Is at Risk for Preterm Labor?
Preterm labor and delivery can happen to any pregnant woman. But they happen more often to some women than to others. Researchers continue to study preterm labor and birth. They have identified some risk factors, but still cannot predict which women will give birth too early. Having a risk factor does not mean a woman will have preterm labor or preterm birth.

Three groups of women are at greatest risk of preterm labor and birth:

• Women who have had a previous preterm birth
• Women who are pregnant with twins, triplets or more
• Women with certain uterine or cervical abnormalities

If you have any of these three risk factors, it's especially important for you to know the signs and symptoms of preterm labor and what to do if they occur.

Lifestyle and Evironmental Risks
Some studies have found that certain lifestyle and environmental factors may put a woman at greater risk of preterm labor. These factors include:

• Late or no prenatal care
• Smoking
• Drinking alcohol
• Using illegal drugs
• Exposure to the medication DES
• Domestic violence, including physical, sexual or emotional abuse
• Lack of social support
• Stress
• Long working hours with long periods of standing

Medical Risks
Certain medical conditions during pregnancy may increase the likelihood that a woman will have preterm labor. These conditions include:

• Urinary tract infections, vaginal infections, sexually transmitted infections and possibly other infections
• Diabetes
• High blood pressure
• Clotting disorders (thrombophilia)
• Bleeding from the vagina
• Certain birth defects in the baby
• Being pregnant with a single fetus after in vitro fertilization (IVF)
• Being underweight before pregnancy
• Obesity
• Short time period between pregnancies (less than 6-9 months between birth and the beginning of the next pregnancy)

Researchers also have identified other risk factors. For instance, African-American women, women younger than 17 or older than 35, and poor women are at greater risk than other women. Experts do not fully understand why and how these factors increase the risk that a woman will have preterm labor or birth.

Preventing Preterm Labor and Birth
You can help in preventing preterm birth by becoming aware of the symptoms of preterm labor and following some simple instructions. The key to preventing preterm birth if preterm labor occurs is to get medical assistance quickly.

Some medications sometimes work to stop labor if they are given early enough. Medications called glucocorticoids, if given 24 hours before birth, can help to accelerate the baby's lung and brain maturity, thus cutting down on some of the worst health problems a preterm baby has. Only if a woman receives medical care quickly can these drugs be helpful, so knowing what to look for is essential.

Symptoms of Preterm Labor
Remember, preterm labor is any labor that occurs between 20 weeks and 37 weeks of pregnancy. Here are the symptoms:

• Contractions (your abdomen tightens like a fist) every 10 minutes or more often
• Change in vaginal discharge (leaking fluid or bleeding from your vagina)
• Pelvic pressure—the feeling that your baby is pushing down
• Low, dull backache
• Cramps that feel like your period
• Abdominal cramps with or without diarrhea

If you start to have any of these symptoms between 20 weeks and 37 weeks of pregnancy, follow the instructions in the section below "What to do if you have symptoms of preterm labor."

Don't let anyone tell you that these symptoms are "normal discomforts of pregnancy"! If any of them (you don't need to have all of them) happen before your 37th week of pregnancy, you need to do something about it.

What to Do if You Have Symptoms of Preterm Labor?
Call your health care provider or go to the hospital right away if you think you are having preterm labor. Your provider may tell you to:

• Come to the office or go to the hospital for evaluation.
• Stop what you are doing and rest on your left side for one hour.
• Drink 2–3 glasses of water or juice (not coffee or soda).

If the symptoms get worse, or don't go away after one hour, call your health care provider again or go to the hospital. If the symptoms go away, take it easy for the rest of the day. If the symptoms stop but come back, call your health care provider again or go to the hospital.

When you call your provider, be sure to tell the person on the phone that you are concerned about the possibility of preterm labor. The only way your provider can know if preterm labor is starting is by doing an internal examination of your cervix (the bottom of your uterus). If your cervix is opening up (dilating), preterm labor could be beginning.

You and your health care provider are a team, working together to have a healthy pregnancy and healthy baby. Your team works best when both of you participate fully, so your knowledge about preterm labor can be essential in helping to prevent a preterm birth. Talk to your health care provider about all of this, and be sure to keep all of your prenatal care appointments. Preterm birth is one of the complications of pregnancy that health care providers are working hard to eliminate. Your participation in this effort is just as important as theirs!

For more information, go to Treatment of Preterm Labor.

Learn more about the March of Dimes Campaign to Reduce Preterm Birth.