What Is Premature Labor and Birth?

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Most pregnancies last about 40 weeks, or just more than nine months. Labor that begins before 37 weeks is called premature or preterm labor. A birth that occurs before 37 weeks is considered a premature or preterm birth.

African American baby in hospital incubator

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Babies born prematurely are at higher risk of being born with serious and long-term health problems. Premature birth is the most common cause of infant death and is the leading cause of long-term disability related to the nervous system in children.

Detecting premature labor early increases the chance that the pregnancy can continue to term. It can also give the baby a better chance of survival.

According to the Centers for Disease Control and Prevention, in 2019, one in every 10 infants in the United States was born prematurely.

Signs and Symptoms

If you are experiencing contractions before 37 weeks, this could indicate preterm labor.

Signs and symptoms include:

  • Mild abdominal cramps, with or without diarrhea
  • A change in the type of vaginal discharge—watery, bloody, or with mucus
  • An increase in the amount of vaginal discharge
  • Pelvic or lower abdominal pressure
  • Constant, low, dull backache
  • Regular or frequent contractions or uterine tightening, often painless
  • Ruptured membranes, where your water breaks with a gush or a trickle of fluid

If you have any signs or symptoms of preterm labor, you should call your healthcare provider immediately or go to the hospital. In particular, you must seek immediate care if you have had more than six contractions in an hour or if you are experiencing fluid or blood leaking from your vagina.

You will need to be examined to see whether you are in premature labor. This will be done through a physical exam and/or an ultrasound.

Healthcare professionals may also conduct a test to detect whether a protein called fetal fibronectin is being produced. This test may be performed on those who show signs of premature labor and can help predict whether someone experiencing these symptoms will have a premature delivery.

Experiencing premature labor does not automatically mean that you will have a preterm birth. According to the American College of Obstetricians and Gynecologists, preterm contractions will stop on their own for about three in 10 people.

False Labor Contractions

In the later stages of pregnancy, you may experience false labor contractions that make you think you are going into labor when you are not. These types of contractions are generally referred to as Braxton Hicks contractions.

They are common and normally felt during the second and third trimesters. However, they can be painful and may be mistaken for labor. They differ from true labor contractions as they do not get longer, stronger, and more frequent as time goes on.

While false labor contractions are not uncommon and not normally a cause for concern, contact your healthcare provider if you are worried or unsure what to do.

Causes

The causes of premature labor and birth are only partially understood. Many factors, including medical, psychosocial, and biological factors, are thought to play a role. The situations leading to preterm labor and premature birth can be categorized in a couple of ways.

Spontaneous Premature Labor and Birth

This is an unintentional and unplanned delivery before the 37th week of pregnancy. It can happen for several reasons, including infection or inflammation, although the exact cause is usually unknown.

Medically Indicated Premature Birth 

Your healthcare provider may recommend a premature delivery if you experience a serious medical condition—such as preeclampsia. Healthcare professionals will try to delay delivery as long as possible so that the baby can develop and grow as much as possible.

Research by the National Institute of Child Health and Human Development indicates that even babies born at 37 or 38 weeks of pregnancy are at higher risk for poor health outcomes than those born at or later than 39 weeks.

Risk Factors

Several factors are known to increase the risk for premature labor and birth. Some of these factors can be changed to help reduce the risk, while others cannot.

Factors that put someone at high risk include:

  • Having experienced premature labor or birth before
  • Being pregnant with twins, triplets, or more
  • Pregnancy resulting from assisted reproductive technology, including in vitro fertilization
  • Infections, including certain vaginal, urinary tract, and sexually transmitted infections
  • High blood pressure
  • Certain developmental abnormalities in the fetus
  • Being underweight or obese before pregnancy
  • A period of fewer than six months between a birth and the beginning of the next pregnancy
  • Placenta previa, where the placenta grows in the lowest part of the uterus and covers all or part of the opening to the cervix
  • Being at risk for rupture of the uterus—for example, if you have had a prior cesarean delivery or have had a uterine fibroid removed
  • Diabetes, including gestational diabetes
  • Blood clotting problems

Factors that increase someone’s risk of premature labor and birth include:

  • Ethnicity
  • Age—those younger than age 18 or older than age 35
  • Late or no health care during pregnancy
  • Smoking
  • Drinking alcohol
  • Using illegal drugs
  • Domestic violence, including physical, sexual, or emotional abuse
  • Lack of social support
  • Stress
  • Long working hours with long periods of standing
  • Exposure to certain environmental pollutants

Treatment

If you are experiencing premature labor, a healthcare professional will manage it based on what they think is best for your and your baby’s health.

You may be given medication to help with the baby’s development, to reduce the risk of complications, and to help delay the delivery. These include:

  • Corticosteroids: These help speed up the development of the lungs, brain, and digestive organs. A single course may be recommended between 24 and 34 weeks of pregnancy for those at risk of delivery within seven days.
  • Magnesium sulfate: This is given to reduce the risk of cerebral palsy and problems with physical movement.
  • Tocolytics: These are used to delay delivery for at least 48 hours. This delay can allow more time for the other medications to work and if a transfer is needed to a hospital with specialized care for preterm babies.

Treatment options to prevent premature labor and birth include:

  • Progesterone: This is the only preventive drug therapy available. It is a hormone that is produced by the body during pregnancy and is given to certain people at risk of premature birth.
  • Cerclage: This is a surgical procedure that is used in those who have a weak cervix and have experienced early pregnancy loss.

Bed rest is not recommended for those at risk of premature birth. It can increase the risk of blood clots, bone weakening, and loss of muscle strength.

If your baby is born prematurely, they will be cared for in a neonatal intensive care unit (NICU). The care the baby will need will depend on how early they are born. Some babies need to stay in the NICU for weeks or even months.

A Word From Verywell

If you experience any of the symptoms of premature labor, do not hesitate to seek medical care. Call your healthcare provider immediately, or go to the nearest emergency room. Getting help as soon as possible can increase your baby’s chance of survival and may allow you to carry your pregnancy to term.

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9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institute of Child Health and Human Development. Preterm labor and birth. Updated January 2017

  2. Centers for Disease Control and Prevention. Preterm birth. Updated October 2020.

  3. The American College of Obstetricians and Gynecologists. Preterm labor and birth. Updated March 2021

  4. National Institute of Child Health and Development. How do health care providers diagnose preterm labor? Updated January 2017

  5. Cleveland Clinic. True vs. false labor. Updated January 1, 2018.

  6. The American College of Obstetricians and Gynecologists. How to tell when labor begins. Updated May 2020

  7. National Institute of Child Health and Human Development. What causes preterm labor and birth? Updated January 2017.

  8. National Institute of Child Health and Development. What are the risk factors for preterm labor and birth? Updated January 2017

  9. National Institute of Child Health and Development. What treatments are used to prevent preterm labor and birth? Updated January 2017.