Premature Birth

More than a half million babies in the United States—that's 1 in every 8—are born premature each year. Learn more about premature birth, risk factors, consequences, and opportunities for prevention.

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 40 weeks).

Important growth and development occur throughout pregnancy – all the way through the final months and weeks. Although most babies born a few weeks early do well with no health consequences, some do 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.

Most preterm deliveries happen spontaneously and without a known cause. Doctors sometimes decide to deliver a baby early because of concerns for the health of the mother or the baby. Medical intervention for an early delivery should only be considered when there is a medical reason to do so.

The more preterm a baby is born, the more severe his or her health problems are likely to be. Although babies born very preterm are a small percent of all births, preterm delivery is the most frequent cause of infant deaths. Some premature babies 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 [PDF - 64KB],
• Cerebral palsy,
• Breathing and respiratory problems,
• Vision and hearing loss, and
• Feeding and digestive problems.

Warning Signs of Preterm Labor

In most cases, preterm labor begins unexpectedly and with no known cause.

The warning signs are—

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

Risk Factors

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

The known risk factors are—

• Carrying more than one baby (twins, triplets, quadruplets or more).
• Having a previous preterm birth.
• Black race
• 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 most women who have a premature birth have no known risk factors. There are things that women can do to help their health and lower the 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, infections, race and ethnicity, nutrition, and environment may interact to put some women at greater risk for a premature delivery.

More Information

• 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.
• Premature Birth — CDC's Division of Reproductive Health
  Promotes optimal reproductive, maternal, 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.

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.