Preterm labor

• Preterm labor and delivery can happen to any pregnant woman.
• Women can take steps to reduce the risk of preterm labor.
• Know the signs of preterm labor and what to do about them.

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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 12 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. The earlier the birth, the greater the risk.

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 very preterm are at a very high risk for brain 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. The effects of premature 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?
There are no easy answers. Stress might play a part for some women, personal health history or infection for others, or smoking or drug use for others. With funding from the March of Dimes and others, researchers are studying how various factors contribute to the complex problem of premature labor and birth.

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 generally predict which women will give birth too early. Having a risk factor does not mean a woman will have preterm labor or preterm birth. It just means that she is at greater risk than other women.

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

1. Women who have had a previous preterm birth
2. Women who are pregnant with twins, triplets or more
3. 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 environmental 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
• Exposure to certain environmental pollutants

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 and preeclampsia 
• Clotting disorders (thrombophilia)
• Bleeding from the vagina 
• Certain birth defects in the baby
• Being pregnant with a single fetus that is the result of 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)

Groups at increased risk
Researchers have also identified certain groups that are at increased risk of having a premature baby. These groups include:

• African-American women
• Women younger than 17 and older than 35
• Women who have a low income

Preventing preterm labor and birth
You can help prevent preterm birth by learning the symptoms of preterm labor and following some simple instructions. The first thing to do is to get medical care both before and during pregnancy. If you do have preterm labor, get medical help quickly. This will improve the chances that you and your baby will do well.

Medications sometimes slow or stop labor if they are given early enough. Drugs called corticosteroids, if given 24 hours before birth, can help the baby's lungs and brain mature. This can prevent some of the worst health problems a preterm baby has. Only if a woman receives medical care quickly can drugs be helpful. Knowing what to look for is essential.

Treatment with a form of the hormone progesterone may help prevent premature birth in some women who have already had a premature baby.

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!

April 2008/April 2010