Preterm Labor

What is preterm labor?

Preterm or premature labor is labor that begins early — before 37 weeks of pregnancy. A normal pregnancy period (fetal development) is about 40 weeks. A pregnancy is “at term” at 37 weeks — anything before 37 weeks is called preterm. Labor is the process your body goes through to prepare for childbirth. Common signs of labor include contractions (tightening of the muscles in your uterus) and your water breaking (rupture of membranes). If you’re experiencing preterm labor, your cervix (lowest end of your uterus) may open (dilate) earlier than usual.

Preterm labor may result in premature birth (being born early). However, labor can often be stopped to allow the fetus more time to grow and develop in the uterus. Treatments to stop premature labor include bed rest, intravenous (in your vein) fluids and medicines to relax your uterus.

In some cases, labor’s induced before the fetus reaches term. This typically happens when there’s a medical reason for delivery. Examples could be preeclampsia (high blood pressure during pregnancy), placental abruption or the fetus isn’t growing (fetal growth restriction).

What is premature birth?

Premature birth (or preterm birth) is when a baby is born before 37 weeks of pregnancy. Babies born before 37 weeks can have health complications like trouble breathing or low birth weight.

What triggers preterm labor?

There isn’t one trigger for preterm labor. Several factors can play a role in your body going into labor too soon. Some of these factors are related to your medical history, previous pregnancies and lifestyle. Sometimes people with no known risk factors have preterm labor.

Can preterm labor be stopped?

Sometimes, but it’s usually temporary. If you go into preterm labor, your healthcare provider may recommend certain medications to stop or delay labor. If those medications don’t work, other medications may help prepare the fetus for an early birth by maturing its lungs and organs.

How do you know if you're in preterm labor?

It’s important to learn the signs of preterm labor. Call your healthcare provider right away if you have any of the following symptoms and if the symptoms don’t go away in one hour, or if the pain is severe and persistent:

• Four or more contractions (or tightening and relaxing of the muscles in your uterus) in one hour that don’t go away after changing your position or relaxing.
• Regular tightening or low, dull pain in your back that either comes and goes or is constant (but isn’t relieved by changing positions or other comfort measures).
• Lower abdominal cramping that might feel like gas pain (with or without diarrhea).
• Increased pressure in your pelvis or vagina.
• Persistent menstrual-like cramps.
• Increased vaginal discharge or discharge that’s mucus-like or tinged pink.
• Leaking of fluid from your vagina. This could be amniotic fluid.
• Vaginal bleeding.
• Flu-like symptoms such as nausea and vomiting.
• Decreased fetal movements (if you don’t feel at least six movements in one hour).

How do I check for contractions?

You may be having Braxton Hicks contractions, a type of practice contraction that helps prepare you for the real thing. Real contractions get closer together, more painful and don’t stop if you rest or change positions. If you aren’t sure if what you feel is a real contraction, contact your healthcare provider to be sure.

What causes preterm labor?

Many factors can contribute to preterm labor. Some are within your control, while others aren’t.

The three risk factors that make you most likely to go into premature labor are:

• You’ve had a premature baby in the past.
• You’re pregnant with twins, triplets or more.
• You have a problem or had a problem in the past with your uterus, cervix or vagina.

Pregnancy risk factors for preterm labor

• You experienced vaginal bleeding throughout your pregnancy.
• You’re pregnant via IVF.
• You’re pregnant with a baby suspected of having a congenital disability.
• Short spacing between pregnancies.

Age and race risk factors for preterm labor

• You’re younger than 17 or older than 35.
• You’re Black.

Lifestyle risk factors for preterm labor

• Lack of prenatal care.
• You’re underweight or overweight before pregnancy.
• You don’t gain enough weight during pregnancy.
• You consume a poor diet.
• You smoke cigarettes, drink alcohol or use illegal drugs.
• You have a physically demanding job where you stand for several hours a day or work long hours.
• You’re highly stressed or anxious.
• You’re exposed to teratogens like chemicals, lead, radiation or other harmful substances.

Medical risk factors for preterm labor

• Untreated vaginal infections (urinary tract infections, sexually transmitted infections or other uterine or vaginal infections).
• Connective tissue disorders like Ehlers-Danlos syndrome (also called EDS).
• Placental problems like placental abruption or placenta previa.
• Too much amniotic fluid (polyhydramnios) or too little amniotic fluid (oligohydramnios).
• You have a short cervix or irregularly shaped uterus (like septate uterus or bicornuate uterus).
• You’ve had prior surgeries on your cervix or uterus.
• You have a medical condition like diabetes, high blood pressure or blood clotting disorders.
• You have intrahepatic cholestasis of pregnancy (also called ICP), a liver condition that happens during pregnancy.

How is preterm labor diagnosed?

Your healthcare provider diagnoses preterm labor by examining your cervix. If your cervix is effaced (thinned) and dilated (open), you may be in preterm labor. In addition to a pelvic exam, your provider may perform the following:

• Ultrasound: An ultrasound can help determine the size of the fetus and its position in your uterus and check for problems with the placenta or with your amniotic fluid.
• Monitor contractions: Your provider may hook you up to a monitor that measures your contractions.
• Fetal fibronectin test: Your provider takes a sample of your vaginal fluid to check for fetal fibronectin. This is a protein that helps the amniotic sac stick to your uterus. If it’s in your discharge, it could mean labor has begun.

How do doctors manage preterm labor?

If you’re in premature labor, you might need medicine to slow or stop labor. If the labor has progressed and can’t be stopped, your provider may need to deliver the fetus early. There are also medications to help the fetus’s lungs and organs if they’re born early. Your provider will evaluate:

• How many weeks pregnant you are.
• If it’s safe for the fetus to be born.
• The reason you may be in early labor (such as due to a medical condition, an issue with the placenta or infection).

What medications are used for preterm labor?

The goal of medication is to stop labor from progressing and give the fetus as much time as possible to grow. The following medications treat preterm labor:

• Tocolytics: This medication stops contractions for up to 48 hours to delay preterm birth. Once labor is delayed, your provider can give you magnesium sulfate or corticosteroids. This also gives them time to transfer you to a hospital with a neonatal intensive care unit (NICU).
• Magnesium sulfate: This medication is given through an IV to help reduce the fetus’s risk of cerebral palsy and problems with physical movement. It’s given if you’re less than 32 weeks pregnant and at risk for delivery in the next 24 hours.
• Corticosteroids: Steroids develop the fetus’s lungs, digestive organs and brain before delivery. They’re typically given between 24 and 34 weeks of pregnancy.

If you have a history of preterm birth, your obstetrician may recommend medication to prevent you from going into labor too soon. The most commonly used medication is progesterone. It involves inserting a progesterone suppository into your vagina. In some cases, your provider will recommend a cervical cerclage. It’s a procedure in which your cervix is stitched closed to prevent it from dilating.

How can I prevent going into labor early?

It’s hard to prevent going into labor early, but there are some ways to lower your risk for preterm labor. Some things you can do are:

• Don’t smoke cigarettes, drink alcohol, use recreational drugs or improperly use prescription drugs.
• Get to a healthy weight before pregnancy and gain an appropriate amount of weight during pregnancy.
• Eat healthy foods and take a prenatal vitamin. Find ways to reduce or manage your stress levels. Stay active, go for walks, read books or take time to relax every day.
• Go to all prenatal appointments and schedule a cleaning with your dentist. There’s a link between your gum health and preterm labor.
• Get treated for or manage any medical conditions you have like hypertension, gestational diabetes, depression or vaginal infections.
• Space your pregnancies by at least 12 to 18 months.

When should you contact your healthcare provider about preterm labor?

Contact your healthcare provider immediately if you notice any of the following signs of preterm labor:

• Abnormal vaginal discharge (leaking fluid) or bleeding.
• Contractions or cramping, with or without diarrhea.
• Ongoing pain in the lower back.
• Pressure in the pelvis or abdomen.
• Your “water breaking.”

A note from Cleveland Clinic

Preterm (or premature) labor can lead to the fetus being born too early. Contact your provider right away if you notice signs of preterm labor like contractions, an increase in vaginal discharge, bleeding or pelvic pain. Luckily, there are things your healthcare provider can do to slow your labor. The longer the fetus stays in your uterus, the less likely it’ll have health complications. You may be at higher risk for preterm labor if you’re carrying twins or have a history of preterm labor or premature birth. Staying healthy throughout your pregnancy and managing existing health conditions is the best way to prevent premature labor.