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This topic covers how preterm labor affects the pregnant woman. If you want to know how it affects the baby after he or she is born, see the topic Reference Premature Infant.
What is preterm labor?
Preterm labor is labor that comes too early—between 20 and 37 weeks of pregnancy.
In labor, the Reference uterus Opens New Window contracts to open the Reference cervix Opens New Window Reference Opens New Window. This is the first stage of childbirth. In a full-term pregnancy, this doesn't happen until at least week 37.
Preterm labor is also called premature labor.
What are the risks of preterm labor and preterm birth?
The earlier a baby is delivered, the higher the chances that he or she will have serious problems. This is because many of the baby's organs—especially the heart and lungs—aren't fully grown yet.
For infants born before 24 weeks of pregnancy, the chances of survival are extremely slim. Many who do survive have long-term health problems. They may also have trouble with learning and talking and with moving their body (poor motor skills).
What causes preterm labor?
Causes of preterm labor include:
- The placenta separating early from the uterus. This is called Reference placenta abruptio Opens New Window.
- Being pregnant with more than one baby, such as twins or triplets.
- An infection in the mother's uterus that leads to the start of labor.
- Problems with the uterus or cervix.
- Drug or alcohol use during pregnancy.
- The mother's water (amniotic fluid) breaking before contractions start.
Often the cause isn't known.
Sometimes a doctor uses medicine or other methods to start labor early because of pregnancy problems that are dangerous to the mother or her baby.
What are the symptoms?
It can be hard to tell when labor starts, especially when it starts early. So watch for these symptoms:
- Regular contractions for an hour. This means about 4 or more in 20 minutes, or about 8 or more within 1 hour, even after you have had a glass of water and are resting.
- Leaking or gushing of fluid from your vagina. You may notice that it is pink or reddish. This is called a rupture of membranes, also known as your water breaking. When this happens before contractions start, it's called Reference premature rupture of membranes Opens New Window, or PROM. When it happens before 37 weeks of pregnancy, it is called preterm premature rupture of membranes, or pPROM.
- Pain that feels like menstrual cramps, with or without diarrhea.
- A feeling of pressure in your pelvis or lower belly.
- A dull ache in your lower back, pelvic area, lower belly, or thighs that doesn't go away.
- Not feeling well, including having a fever you can't explain and being overly tired. Your belly may hurt when you press on it.
If your contractions stop, they may have been Reference Braxton Hicks contractions Opens New Window. These are a sometimes uncomfortable—but not painful—tightening of the uterus. They are like practice contractions. But sometimes it can be hard to tell the difference.
How is preterm labor diagnosed?
If you think you have symptoms of preterm labor, call your doctor or certified nurse-midwife. He or she 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.
Checking the baby's heartbeat and doing an Reference ultrasound Opens New Window can give your doctor or midwife a good picture of how your baby is doing. Amniotic fluid can be tested for signs that your baby's lungs have grown enough for delivery.
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.
How is it treated?
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:
- Try to delay the birth with medicine. This may or may not work.
- Use antibiotics to treat or prevent infection. If your amniotic sac has broken early, you have a high risk of infection and must be watched closely.
- Give you steroid medicine to help prepare your baby's lungs for birth.
- Treat any other medical problems causing trouble in pregnancy.
- Allow the labor to go on because delivery is safer for the mother and baby than letting the pregnancy go on.
Frequently Asked Questions
Learning about preterm labor:
|By:||Reference Healthwise Staff||Last Revised: Reference May 10, 2012|
|Medical Review:||Reference Sarah Marshall, MD - Family Medicine
Reference William Gilbert, MD - Maternal and Fetal Medicine