Preterm labor and premature birth


  • Preterm labor can lead to premature birth. Babies born prematurely are more likely to have health problems than babies born on time.

  • Some women are more likely than others to have preterm labor and premature birth.

  • You can reduce your risk factors to help make you less likely to have preterm labor. 

  • Learn the signs of preterm labor and what to do if they happen to you. 

What is preterm labor?

Even if you do everything right during pregnancy, you can still have preterm labor. Preterm labor is labor that happens too soon, before 37 weeks of pregnancy. Babies born this early are called premature. Premature babies can have serious health problems at birth and later in life. About 1 in 10 babies is born prematurely each year in this country. 

What causes preterm labor and premature birth?

Sometimes we don’t know for sure what causes preterm labor and premature birth. Any woman can have preterm labor and give birth early, even if she’s done everything right during pregnancy.

We do know some things make a woman more likely than others to have preterm labor and premature birth. These are called risk factors. Having a risk factor doesn’t mean for sure that you’ll have preterm labor or give birth early. But it may increase your chances. Talk to your health provider about what you can do to help reduce your risk.

Because many premature babies are born with low birthweight, many risk factors for preterm labor and premature birth are the same as for having a low-birthweight baby. Low birthweight is when a baby is born weighing less than 5 pounds, 8 ounces.

These three risk factors make you most likely to have preterm labor and give birth early:

  1. You’ve had a premature baby in the past
  2. You’re pregnant with multiples (twins, triplets or more).  
  3. You have problems with your uterus or cervix now or you’ve had them in the past.

Medical risk factors for preterm labor and premature birth

  • Getting late or no prenatal care. Prenatal care is medical care you get during pregnancy.
  • Bleeding from the vagina in the second or third trimester 
  • Being underweight or overweight before pregnancy or not gaining enough weight during pregnancy
  • Having certain health conditions, like high blood pressure, preeclampsia, diabetes or thrombophilias (blood clotting disorders). Or having certain infections during pregnancy, like a sexually transmitted disease (also called STD) or other infections of the uterus, urinary tract or vagina. 
  • Preterm premature rupture of the membranes (also called PPROM). This is when the sac around the baby breaks early, causing labor to start. 
  • Being pregnant after in vitro fertilization (also called IVF). IVF is a fertility treatment used to help women get pregnant.  
  • Being pregnant with a baby who has certain birth defects, like congenital heart defects or spina bifida
  • Getting pregnant too soon after having a baby. Wait at least 18 months between giving birth and getting pregnant again. Talk to your provider about how long to wait between pregnancies if you're older than 35 or you've had a miscarriage or stillbirth. Miscarriage is the death of a baby in the womb before 20 weeks of pregnancy. Stillbirth is the death of a baby in the womb after 20 weeks of pregnancy. 
  • Having a family history of premature birth. This means someone in your family (like your mother, grandmother or sister) has had a premature baby. If you were born prematurely, you’re more likely than others to give birth early. 
  • Exposure to the medicine DES, a man-made form of the hormone estrogen. This includes being exposed to DES in the womb (your mother took DES when she was pregnant with you).

Risk factors in your everyday life for preterm labor and premature birth

  • Smokingdrinking alcohol, using street drugs or abusing prescription drugs
  • Having a lot of stress in your life, including having little education, low income, being unemployed or having little support from family and friends 
  • Being single
  • Domestic violence. This is when your partner hurts or abuses you. It includes physical, sexual and emotional abuse. 
  • Working long hours or having to stand a lot
  • Being exposed to pollutants, like air pollution and harmful chemicals at work 

Other risk factors for preterm labor and premature birth: Age and race/ethnicity 

Being younger than 17 or older than 35 makes you more likely than other women to give birth early. Race/Ethnicity is a risk factor, too. In the United States, black women are more likely to give birth early. Almost 17 percent of black babies are born prematurely each year. Just more than 10 percent of Native American and Hispanic babies are born early, and less than 10 percent of white and Asian babies. We don’t know why race plays a role in premature birth; researchers are working to learn more about it.   

Can you reduce your risk for preterm labor and premature birth?

Sometimes. There may be things you can do to help reduce some risk factors. Here’s how: 

  • Don’t smoke, drink alcohol use street drugs or abuse prescription drugs. Ask your provider about programs in your area that can help you quit. 
  • Go to your first prenatal care appointment as soon as you think you’re pregnant. During pregnancy, go to all your prenatal care appointments, even if you’re feeling fine. Prenatal care helps your provider make sure you and your baby are healthy. 
  • Talk to your provider about your weight. Ask how much weight you should gain during pregnancy. Try to get to a healthy weight before your next pregnancy. 
  • Get treated for chronic health conditions, like high blood pressure, diabetes and thyroid problems. 
  • Protect yourself from infections. Wash your hands with soap and water after using the bathroom or blowing your nose. Don’t eat raw meat or fish. Have safe sex. Don’t touch cat poop
  • Reduce your stress. Exercise and eat healthy foods. Ask for help from family and friends. Get help if your partner abuses you. Talk to your boss about how to lower your stress at work. 
  • Wait at least 18 months between giving birth and getting pregnant again. See your provider for a preconception checkup before your next pregnancy.

What are the signs of preterm labor?

We know that preterm labor can lead to early birth. So how do you know if you’re in preterm labor? Learn the signs of preterm labor so you know what to do if preterm labor happens to you.

Are there treatments for preterm labor?

Yes. You may get treatments to help prevent or stop preterm labor. Or you may get treatments to help improve your baby's health before birth. Talk to your provider about which treatments may be right for you. 

Last reviewed: March, 2016