Premature Labor

Pregnancy is normally a time of happiness and anticipation, but it can also be a time of unknowns. Many women have concerns about what is happening with their baby. Is everything okay? Some women wonder about going into labor early. Premature labor occurs in about 12% of all pregnancies. However, knowing the symptoms and avoiding particular risk factors can lower a woman’s chance of premature labor.

What is premature labor?

A normal pregnancy should last about 40 weeks. Occasionally, labor may begin prematurely before the 37th week of pregnancy because uterine contractions cause the cervix to open earlier than normal. When this happens, the baby is born premature and can be at risk for health problems. Fortunately, due to research, technology and medicine, the health of premature babies is improving.

What risk factors place me at a high risk for premature labor?

Certain factors may increase a woman’s risk of having premature labor, although the specific causes of premature labor are not known. However, having a specific risk factor does not mean a woman is predetermined to have premature labor. A woman may have premature labor for no apparent reason. If you have any of these risk factors, it’s important to know the symptoms of premature labor and what you should do if they occur.

  • Women are at greatest risk for premature labor if:
    • They are pregnant with multiples
    • They have had a previous premature birth
    • They have certain uterine or cervical abnormalities
  • Medical risk factors include:
    • Recurring bladder and/or kidney infections
    • Urinary tract infections, vaginal infections, and sexually transmitted infections
    • Infection with fever (greater than 101 degrees F) during pregnancy
    • Unexplained vaginal bleeding after 20 weeks of pregnancy
    • Chronic illness such as high blood pressure, kidney disease or diabetes
    • Multiple first trimester abortions or one or more second trimester abortions
    • Underweight or overweight before pregnancy
    • Clotting Disorder (thrombophilia)
    • Being Pregnant with a single fetus after in vitro fertilization (IVF)
    • Short time between pregnancies (less than 6-9 months between birth and beginning of the next pregnancy)
  • Lifestyle risks for premature labor include:
    • Little or no prenatal care
    • Smoking
    • Drinking alcohol
    • Using illegal drugs
    • Domestic violence, including physical, sexual or emotional abuse
    • Lack of social support
    • High levels of stress
    • Low income
    • Long working hours with long periods of standing

What are warning signs of premature labor?

It may be possible to prevent a premature birth by knowing the warning signs and calling your health care provider if you suspect you are having premature labor. Warning signs and symptoms of premature labor include:

  • A contraction every 10 minutes, or more frequently within one hour (five or more uterine contractions in an hour)
  • Watery fluid leaking from your vagina (this could indicate that your bag of water is broken)
  • Menstrual-like cramps felt in the lower abdomen that may come and go or be constant
  • Low, dull backache felt below the waistline that may come and go or be constant
  • Pelvic pressure that feels like your baby is pushing down
  • Abdominal cramps that may occur with or without diarrhea
  • Increase or change in vaginal discharge

What does a contraction feel like?

As the muscles of your uterus contract, you will feel your abdomen harden. As the contraction goes away, your uterus becomes soft. Throughout pregnancy, the layers of your uterus will tighten irregularly which are usually not painful. These are known as Braxton-Hicks contractions and are usually irregular and do not open the cervix. If these contractions become regular or more frequent (one every 10-12 minutes for at least an hour) they may be premature labor contractions which can cause the cervix to open. It is important to contact your health care provider immediately.

How can I check for contractions?

While lying down, use your fingertips to feel your uterus tighten and soften. This is called “palpation.” During a contraction your abdomen will feel hard all over, not just in one area. However, as your baby grows you may feel your abdomen become firmer in one area and then become soft again.

What should I do if I think I am experiencing premature labor?

If you suspect you are having signs and symptoms of premature labor call your health care provider immediately. This can be a scary time for you but there are some ways you can help to prevent premature labor by becoming aware of the symptoms and following these directions:

  • Empty your bladder
  • Lie down titled towards your left side; this may slow down or stop signs and symptoms
  • Avoid lying flat on your back; this may cause the contractions to increase
  • Drink several glasses of water because dehydration can cause contractions
  • Monitor contractions for one hour by counting the minutes that elapse from the beginning of one contraction to the beginning of the next

If symptoms get worse, or don’t go away after one hour, call your health care provider again or go to the hospital. When you call your health care provider, be sure to mention that you are worried about premature labor. The only sure way to know if you are in premature labor is by examination of your cervix. If your cervix is opening up, premature labor could be starting.

What is the treatment to prevent premature labor from starting or continuing?

  • Magnesium Sulfate is a medication given through an IV, which may cause nausea temporarily. A large dose is given initially and then a smaller continuous dose is given for 12-24 hours or more.
  • Corticosteroid is a medication given 24 hours before birth to help accelerate the baby’s lung and brain maturity.
  • Oral medications are sometimes used to decrease the frequency of contractions, and may make women feel better.

What impact does premature labor have on my pregnancy?

The longer your baby is in the womb, the better the chance he or she will be healthy. Babies who are born prematurely are at higher risks for brain and other neurological complications, as well as breathing and digestive problems. Some premature babies grow up with a developmental delay, and/or have learning difficulties in school. The earlier in pregnancy a baby is born, the more health problems are likely to develop.

Premature labor does not always result in premature delivery. Some women with premature labor and early dilation of the cervix are sometimes put on bed rest until the pregnancy progresses further.

Most babies born prior to 24 weeks have little chance of survival. Only about 50% will survive and the other 50% may die or have permanent problems. However, babies born after 32 weeks have a very high survival rate, and usually do not have long term complications.

Babies born at hospitals with neonatal intensive care units (NICU) do best. If you deliver at a hospital that does not have a NICU, you may be transferred to a nearby hospital.

Last Updated: 11/2006

Compiled using information from the following sources:

March of Dimes,


William’s Obstetrics Twenty-Second Ed. Cunningham, F. Gary, et al, Ch. 36.

Last updated: 11/2006