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Preterm labor is labor that comes too early—between 20 and 37 weeks of pregnancy. In labor, the uterus contracts to open the cervix. This is the first stage of childbirth. In most pregnancies, this happens at 37 to 42 weeks. Preterm labor is also called premature labor.
Preterm labor doesn't always lead to preterm birth, but it may. A baby born too early may have serious problems, such as chronic lung disease. This is because many of the baby's organs, especially the heart and lungs, aren't fully grown yet. The earlier a baby is born, the higher the risk of problems.
Preterm labor can be caused by a problem involving the baby, the mother, or both. Possible causes of preterm labor include being pregnant with more than one baby, an infection, and problems with the placenta, uterus, or cervix. Often a combination of several factors is responsible. Sometimes the cause isn't known.
It can be hard to tell when labor starts. But you may notice one or more symptoms, such as menstrual-like cramps, leaking or gushing of fluid from your vagina, or regular contractions. This means about 6 or more contractions in 1 hour, even after you've had a glass of water and are resting.
If you have symptoms of preterm labor, both you and your baby will be examined and monitored. You may have urine and blood tests to check for problems that can cause preterm labor. Your doctor or midwife will check the baby's heartbeat and do an ultrasound to see how your baby is doing.
Preterm labor isn't always treated. When deciding whether and how to treat it, many things are considered, including your health and your baby's age, weight, and health. Your doctor or midwife may use medicine to try to delay the birth or medicines to prevent infection and prepare your baby for birth.
Preterm labor can be caused by a problem involving the baby, the mother, or both. Often a combination of several factors is responsible. Sometimes the cause isn't known.
Possible causes of preterm labor include:
It's hard to prevent preterm labor, because it usually isn't expected. Also, it's often due to causes that aren't completely understood.
But building some healthy pregnancy habits—such as going to all of your doctor appointments—may help prevent preterm labor and give your baby the best chance to be healthy.
Being pregnant with twins, triplets, or more increases the chances of preterm labor and problems for the babies.
If you had preterm labor in a previous pregnancy, your risk for having it again is high. Your doctor may consider giving you progesterone during your second and third trimesters. This may help lower your risk of preterm labor.
But if you're pregnant with twins or more, progesterone treatment is generally not used to prevent preterm labor even if you had a previous preterm birth. Progesterone does not prevent preterm birth in women pregnant with more than one baby.
It can be hard to tell when labor starts, especially when it starts early. But you may notice one or more symptoms, including:
If your contractions stop, they may have been Braxton Hicks contractions. They're like practice contractions. But sometimes it can be hard to tell the difference.
If preterm labor occurs close to your due date (in the 35th or 36th week of pregnancy), you may be allowed to deliver without delay. Preterm birth at this point in a pregnancy doesn't usually cause serious problems.
But preterm labor doesn't always mean that preterm birth will happen. Your doctor may be able to stop your preterm labor.
When preterm labor can't be stopped, most women can deliver vaginally. But if your health or your baby's health is at risk, you may need a cesarean section.
If a baby is born too early, the baby may have complications, such as bleeding in the brain or chronic lung disease. The earlier a baby is born, the higher the risk.
Preterm labor can be hard to recognize. Get the earliest possible medical care by calling your doctor or your nurse-midwife about signs of preterm labor.
Call your doctor or your nurse-midwife if:
Call your doctor, your nurse-midwife, or the labor and delivery unit of your local hospital if:
If you are having painless or mild contractions that are irregular or more than 15 minutes apart:
If your contractions stop, they were probably Braxton Hicks contractions. These are harmless and normal. Braxton Hicks contractions are often irregularly timed and uncomfortable rather than painful.
Call your doctor or nurse-midwife if you start to have regular contractions.
If you think you have symptoms of preterm labor, your doctor or certified nurse-midwife can check to see if your water has broken, if you have an infection, or if your cervix is starting to dilate. You may also have urine and blood tests to check for problems that can cause preterm labor.
Your doctor or midwife will check the baby's heartbeat and do an ultrasound to see how your baby is doing.
You may have a painless swab test for a protein in the vagina called fetal fibronectin. If the test doesn't find the protein, then you are unlikely to deliver soon. But the test can't tell for certain if you are about to have a preterm birth.
Preterm labor isn't always treated. When deciding whether and how to treat it, many things are considered, including your health and your baby's age, weight, and health.
If you are in preterm labor, your doctor or certified nurse-midwife must compare the risks of early delivery with the risks of waiting to deliver. Depending on your situation, your doctor or midwife may:
Symptoms of preterm labor are warning signs. They don't necessarily mean that you'll have a preterm birth.
If you're less than 37 weeks pregnant and you're having more or stronger contractions than usual, try these things.
Not having enough liquids can cause contractions.
If your contractions get worse during the hour, call your doctor or nurse-midwife, or go to the hospital.
Although stress isn't thought to be a direct cause of preterm labor, try to do less, ask for help, and eat well.
If your contractions are causing changes in your cervix, or if you have signs of infection or preterm prelabor rupture of membranes (pPROM), you may be given medicines to help delay delivery.
Delaying labor even for a short time can allow you to be:
Medicines that may be used to treat preterm labor include:
Certain tocolytic medicines can be dangerous when a fetus is showing signs of distress or for women with certain health conditions (such as heart problems, severe preeclampsia, or poorly controlled diabetes or high blood pressure).
Current as of:
July 11, 2023
Author: Healthwise StaffClinical Review Board: All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.
Current as of: July 11, 2023
Clinical Review Board:
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.
To learn more about Healthwise, visit Healthwise.org.
© 1995-2023 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
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