Preterm Labor

Preterm Labor

Most pregnancies last about 40 weeks. If you go into labor before 37 weeks, you are experiencing preterm labor and have a higher chance of preterm birth. Babies born prematurely may be born with significant health problems, so preterm labor requires immediate medical attention.


Premature babies are born before their body and organs have fully matured. They are often small, with a low birth weight (less than 2,500 grams or 5.5 pounds) and may need help breathing, eating, fighting infection, and staying warm. Babies born before 28 weeks are at the greatest risk for problems.

Premature babies may have the following:

  • Trouble maintaining body temperature or staying warm
  • Breathing problems
  • Heart and blood vessels problems (heart defects and blood and heart rate problems)
  • Blood problems, including low red blood cell counts (anemia), yellow color to the skin from breaking down old red blood cells (jaundice), or low blood sugar (hypoglycemia)
  • Kidney problems
  • Digestive problems, including trouble feeding and poor digestion
  • Nervous system problems, including bleeding in the brain or seizures
  • Infections
  • Long-term health problems

Going into preterm labor increases the risk of delivering prematurely. If you think you are experiencing preterm labor, call your doctor immediately.


The most common symptoms of preterm labor are:

  • Tightening of the uterus (contractions), especially more than 4 in 1 hour
  • Menstrual-type cramps
  • Pressure in the lower belly
  • Backache
  • Diarrhea
  • Change in the type or amount of vaginal discharge. This might be blood, mucus, or watery fluid.
  • “Water breaking,” or a gush of fluid from the vagina

Call your doctor as soon as possible if you are experiencing symptoms of preterm labor. Hoag’s dedicated Obstetrics Emergency Department (OB/ED) is available to help you through your emergency.


For about 3 in 10 women, preterm labor stops on its own. If it does not stop, your doctor may give you medication to delay birth. You may also be put on bed rest, either at home or in the hospital.

Medical treatments and interventions include:

  • Tocolytic medicines. These are used to slow or stop contractions and may be given as an injection or intravenously.
  • Corticosteroids. Because preterm babies’ lungs may not be able to work on their own, these medications are given if your doctor suspects you will deliver early.
  • Cervical cerclage. This procedure is used to stitch the cervix closed. It may be done when the cervix is weak and not able to stay closed.
  • Antibiotics. These are used to treat infection.
  • Delivery. If treatments don’t stop your preterm labor or if your baby is in danger, your doctor will deliver your baby vaginally or through a cesarean section.
Risk Factors

While most women who go into preterm labor have no known risk factors, the following can raise a woman’s risk:

  • Smoking
  • Being younger than 20 or older than 35
  • Long-term illness such as heart disease or kidney disease
  • Using illegal drugs such as cocaine
  • Abnormally shaped uterus
  • Cervix not able to stay closed
  • A history of preterm births
  • Being Black
  • Placenta that separates from the uterus early or is positioned abnormally
  • Early breaking of sac around the baby (premature rupture of membranes)
  • Birth defects in the baby or problems with fetal growth
  • Carrying multiples (twins, triplets, etc.)
The Importance of Prenatal Care

Prenatal care plays an important role in identifying problems and lifestyle factors that can increase the risks for preterm labor and birth. Your doctor can work with you to lower your risk by advising you to quit smoking and prescribing the hormone progesterone, which can help lower your risk if you have had a preterm birth in the past.

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