Why Are Babies Born Early?

Most babies are born healthy at or near their due date. Sometimes, though, babies are born early and might have health problems.

Why Are Some Babies Born Early?

Babies born before 37 weeks are premature. A premature birth is more likely to happen when a mother has a health problem — like diabetes — or does harmful things during her pregnancy, like smoke or drink. If she lives with a lot of stress, that also can make her baby be born too early.

Many things can cause a baby to be born early or with health problems. Some of these things can be controlled, but others can't.

Here's what you can do to have a healthy pregnancy.

How Can I Stay Healthy During Pregnancy?

During pregnancy, help your baby grow strong and healthy. Be sure to:

Start prenatal care as soon as you think you're pregnant. Prenatal care is the health care that you get during pregnancy. All pregnant women should see a health care professional as soon as they think they're pregnant, and should plan regular prenatal visits throughout pregnancy.
Get health problems treated. It's best to have any health problems (like diabetes, depression, or high blood pressure) under control before becoming pregnant. But if you don't, talk to your doctor right away about a treatment plan.
Eat a healthy diet. It's important to eat a variety of healthy foods before and during pregnancy. Take a prenatal vitamin to be sure you're getting enough folic acid, iron, and other important nutrients.
Gain the right amount of weight. How much weight you should gain depends on how much you weighed before you were pregnant. Most women who are at a healthy weight should gain about 25 to 35 pounds during pregnancy. Overweight women should probably gain less.
Don't smoke, drink alcohol, or take illegal drugs. Staying away from tobacco, alcohol, and drugs can help you and your baby avoid many serious health problems, like fetal alcohol syndrome and neonatal abstinence syndrome (NAS). If you do any of these things, get help to quit.
Wait at least 12 months between pregnancies. Increasing the time between pregnancies may lower the chances of preterm birth, especially if you had a premature baby before.

Things You Can't Control During Pregnancy

Some things that may increase the chances of a premature birth are out of your control. This doesn't mean that your baby will be born sick or too early. Remember, most babies are born healthy.

Here are some things you can't control during pregnancy:

Your age. Mothers who are 17 or younger or 35 or older are more likely to have a premature baby. Teen moms are more likely to get high blood pressure during pregnancy and less likely to get the health care they need. Older women are more likely to have health problems before they get pregnant.
The number of babies (multiples). The chances of having a premature baby go up if the mother is pregnant with twins, triplets, or more. More than half of all twins are born early.
Your health. Moms with problems like diabetes, depression, or high blood pressure may need to see their health care professional more often to keep these conditions under control.
Problems with an earlier pregnancy. A woman who has had a previous early delivery, or a baby born with health problems or a birth defect, is more likely to have problems in future pregnancies too.
Other factors. It's not clear why, but black women are more likely to have premature babies than white and Hispanic women.

If you're pregnant or are planning to be, talk with your health care professional. Women who get regular prenatal care are more likely to have a healthier pregnancy and baby.