Labor, Delivery, and Postpartum Care
FAQ087, July 2014



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Preterm (Premature) Labor and Birth

What is preterm labor?

Preterm labor is defined as regular contractions of the uterus resulting in changes in the cervix that start before 37 weeks of pregnancy. Changes in the cervix include effacement (the cervix thins out) and dilation (the cervix opens so that the fetus can enter the birth canal).

What is preterm birth?

When birth occurs between 20 weeks of pregnancy and 37 weeks of pregnancy, it is called preterm birth.

Why is preterm birth a concern?

Preterm birth is a concern because babies who are born too early may not be fully developed. They may be born with serious health problems. Some health problems, like cerebral palsy, can last a lifetime. Other problems, such as learning disabilities, may appear later in childhood or even in adulthood.

Which preterm babies are at greatest risk of health problems?

The risk of health problems is greatest for babies born before 34 weeks of pregnancy. But babies born between 34 weeks and 37 weeks also are at risk.

What are risk factors for preterm birth?

Factors that increase the risk of preterm birth include the following:

  • Having a previous preterm birth
  • Having a short cervix
  • Short interval between pregnancies
  • History of certain types of surgery on the uterus or cervix
  • Certain pregnancy complications, such as multiple pregnancy and vaginal bleeding
  • Lifestyle factors such as low prepregnancy weight, smoking during pregnancy, and substance abuse during pregnancy

Can anything be done to prevent preterm birth if I am at high risk?

If you have had a prior preterm birth and you are planning another pregnancy, a preconception care checkup can help you get in the best possible health before you become pregnant. When you become pregnant, be sure to start prenatal care early. You may be referred to a health care provider who has expertise in managing high-risk pregnancies. In addition, you may be given certain medications or other treatment to help prevent preterm birth if you have risk factors. Treatment is given based on your individual situation and your risk factors for preterm birth.

What are the signs and symptoms of preterm labor and what should I do if I have any of them?

Call your health care provider right away if you notice any of these signs or symptoms:

  • Change in type of vaginal discharge (watery, mucus, or bloody)
  • Increase in amount of discharge
  • Pelvic or lower abdominal pressure
  • Constant low, dull backache
  • Mild abdominal cramps, with or without diarrhea
  • Regular or frequent contractions or uterine tightening, often painless
  • Ruptured membranes (your water breaks with a gush or a trickle of fluid)

How is preterm labor diagnosed?

Preterm labor can be diagnosed only when changes in the cervix are found. Your health care provider may perform a pelvic exam to see if your cervix has started to change. You may need to be examined several times over a period of a few hours. Your contractions also may be monitored.

Your health care provider may do certain tests to determine whether you need to be hospitalized or if you need immediate specialized care. A transvaginal ultrasound exam may be done to measure the length of your cervix. The level of a protein called fetal fibronectin in the vaginal discharge may be measured. The presence of this protein is linked to preterm birth.

If I have preterm labor, will I have a preterm birth?

It is difficult for health care providers to predict which women with preterm labor will go on to have preterm birth. Only about 10% of women with preterm labor will give birth within the next 7 days. For about 30% of women, preterm labor stops on its own.

What happens if my preterm labor continues?

If your preterm labor continues, how it is managed is based on what is thought to be best for your health and your baby’s health. When there is a chance that the baby would benefit from a delay in delivery, certain medications may be given. These medications include corticosteroids, magnesium sulfate, and tocolytics.

What are corticosteroids?

Corticosteroids are drugs that cross the placenta and help speed up development of the baby’s lungs, brain, and digestive organs. Corticosteroids are most likely to help your baby when they are given between 24 weeks of pregnancy and 34 weeks of pregnancy.

What is magnesium sulfate?

Magnesium sulfate is a medication that may be given if you are less than 32 weeks pregnant, are in preterm labor, and are at risk of delivery within the next 24 hours. This medication may help reduce the risk of cerebral palsy that is associated with early preterm birth.

What are tocolytics?

Tocolytics are drugs used to delay delivery for a short time (up to 48 hours). They may allow time for corticosteroids or magnesium sulfate to be given or for you to be transferred to a hospital that offers specialized care for preterm infants. In addition to its role in protecting against cerebral palsy, magnesium sulfate also can be used as a tocolytic drug.

What happens if my labor does not stop?

If your labor does not stop and it looks like you will give birth to your baby early, you and the baby usually will be cared for by a team of health care providers. The team may include a neonatologist, a doctor who specializes in treating problems in newborns. The care your baby needs depends on how early he or she is born. High-level neonatal intensive care units (NICUs) provide this specialized care for preterm infants.

Glossary

Cerebral Palsy: A long-term disability of the nervous system that affects young children in which control of movement or posture is abnormal and is not the result of a recognized disease.

Cervix: The lower, narrow end of the uterus at the top of the vagina.

Corticosteroids: Hormones given to help fetal lungs mature, for arthritis, or for other medical conditions.

Fetal Fibronectin: A protein produced during pregnancy.

Fetus: The developing organism in the uterus from the ninth week of pregnancy until the end of pregnancy.

Magnesium Sulfate: A drug that may help prevent cerebral palsy when it is given to women in preterm labor who are at risk of delivery before 32 weeks of pregnancy.

Neonatologist: A doctor who specializes in the diagnosis and treatment of disorders that affect newborn infants.

Pelvic Exam: A physical examination of a woman’s reproductive organs.

Placenta: Tissue that provides nourishment to and takes waste away from the fetus.

Prenatal Care: A program of care for a pregnant woman before the birth of her baby.

Tocolytics: Medications used to stop or slow preterm labor.

Transvaginal Ultrasound: A type of ultrasound in which a device specially designed to be placed in the vagina is used.

Uterus: A muscular organ located in the female abdomen that contains and nourishes the developing embryo and fetus during pregnancy.

If you have further questions, contact your obstetrician–gynecologist.

FAQ087: Designed as an aid to patients, this document sets forth current information and opinions related to women’s health. The information does not dictate an exclusive course of treatment or procedure to be followed and should not be construed as excluding other acceptable methods of practice. Variations, taking into account the needs of the individual patient, resources, and limitations unique to the institution or type of practice, may be appropriate.

Copyright July 2014 by the American College of Obstetricians and Gynecologists