Premature Birth

More than a half million babies in the United States—that's 1 in every 8—are born premature each year. Some babies are so small they could fit in the palm of your hand. If you're pregnant, learn about the risk factors for premature birth.

What is premature birth? It is a birth that is at least three weeks before a baby’s due date. It is also known as preterm birth (or less than 37 weeks — full term is about 40 weeks).

Prematurity is the leading cause of death among newborn babies. Being born premature is also a serious health risk for a baby. Some babies will require special care and spend weeks or months hospitalized in a neonatal intensive care unit (NICU). Those who survive may face lifelong problems such as—

• Intellectual disabilities,
• Cerebral palsy,
• Breathing and respiratory problems,
• Vision and hearing loss, and
• Feeding and digestive problems.

Although the more preterm a baby is born, the more severe his or her health problems are likely to be, even babies born just a few weeks early can have more health problems than full-term babies. For example, a baby born at 35 weeks is more likely to have—

• Jaundice,
• Breathing problems, and
• Longer hospital stays.

Not only is premature birth an emotional roller coaster for families, there is a tremendous financial toll as well. In 2005, the annual societal economic cost (medical, educational, and lost productivity) of preterm birth in the United States was at least $26.2 billion. The average first year medical costs were about 10 times greater for preterm than for full-term babies.

Doctors sometimes decide to deliver a baby early because of concerns for the health of the mother or the baby. Despite the problems associated with a premature birth, this may be the safest option. However, in most cases preterm labor begins unexpectedly.

The warning signs are—

• 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

Risk Factors

There are some known risk factors for premature birth. But even if a woman does everything “right” during pregnancy, she still can have a premature baby.

The known risk factors are—

• Carrying more than one baby (twins, triplets, quadruplets or more).
• Having a previous preterm birth.
• Problems with the uterus or cervix.
• Chronic health problems in the mother, such as high blood pressure, diabetes, and clotting disorders.
• Certain infections during pregnancy.
• Cigarette smoking, alcohol use, or illicit drug use during pregnancy.

Preterm birth can happen to anyone and many women who have a premature birth have no known risk factors. There are things you can do to help your own health and lower your risk of having a premature baby such as—

• Quit smoking and avoid substances such as alcohol or drugs.
• See your health care provider for a medical checkup before pregnancy.
• Work with your health care provider to control diseases such as high blood pressure or diabetes.
• Get prenatal care early, as soon as you think you may be pregnant, and throughout the pregnancy.
• Discuss concerns during pregnancy with your health care provider, and seek medical attention for any warning signs or symptoms of preterm labor.

Birth is a complex and wonderful process. Fortunately, the outcome for most women is a full term, healthy baby. More research still is needed to understand the risk factors for premature birth, such as how family history, genetics, lifestyle, and environment may interact to put some women at greater risk for a premature delivery.

More Information

March of Dimes Resources

Prematurity Campaign*
More information about premature birth and the March of Dimes prematurity campaign.

Share Your Story* (Spanish language online community also available)
Virtual community for parents with a baby in a neonatal intensive care unit.

PeriStats*
This Web site provides a wealth of national, state, and local perinatal statistics.

Preterm Labor and Birth
More information from the National Institute of Child Health and Human Development.

Premature Babies
The National Library of Medicine provides links to the latest news and research on preterm birth.

Healthy Pregnancy
Learn how to be healthy (before, during, and after pregnancy) and give your baby a healthy start to life.

Maternal and Infant Health: Premature Birth -- CDC's Division of Reproductive Health
Promotes optimal reproductive and infant health. CDC scientists and their partners are collaborating with states, university researchers and partners in health care to understand why preterm births occur, and what can done to prevent prematurity.

CDC's National Center on Birth Defects and Developmental Disabilities
Promotes the health of babies, children, and adults, and enhances the potential for full, productive living.