Preterm Labor

     The length of a pregnancy is 40 weeks.  In most pregnancies, labor starts between 37 and 42 weeks after a woman's last menstrual period.  When it begins before 37 weeks, it is considered preterm.  About 1 of every 10 babies born in the United States is born preterm.  Your baby can have problems if it is born too early.  Serious illness or death can occur because the baby is not yet ready for life on his or her own. 

 

 

    

WHAT IS PRETERM LABOR?

     Labor starts with regular contractions of the uterus.  The cervix thins out (effaces) and opens up (dilates) so the baby can enter the birth canal.  It is not known for certain what causes labor to start.  Hormones produced by the woman, placenta, and fetus play a role.  Changes in the uterus, which may be caused by these hormones, may cause labor to start.  There are many reasons for preterm labor.  In most cases of preterm labor, however, the exact cause is not known. 

 

 

WHY THE CONCERN?

     Preterm birth accounts for most newborn deaths.  Growth and development in the last part of pregnancy are vital to the baby's health.  The earlier the baby is born, the greater the chance he or she will have health problems.  Preterm babies (also called premature babies or "preemies") tend to grow more slowly than term babies.  They also may have problems with their eyes, ears, breathing, and nervous system.  Learning and behavioral problems are more common in children who were preterm babies.

 

 

SIGNS OF PRETERM LABOR

     If preterm labor is found early enough, delivery may be prevented or postponed in some cases.  This will give your baby extra time to grow and mature.  Even a few more days may mean a healthier baby.  Sometimes the signs that preterm labor may be starting are fairly easy to detect.  The box below will list the early signs of preterm labor.  If you have any of these symptoms, don't wait. Call your doctor's office or go to the hospital.

 

 

DIAGNOSING PRETERM LABOR

    It is common for women to have Braxton Hicks contractions, sometimes called false labor, during the last part of pregnancy.  These contractions may be painful and regular, but usually go away within an hour or so with rest.  If you have contractions that occur 4 times every 20 minutes or if you have contractions 8 times an hour that last for more than an hour, call your doctor's office right away. 

    

WARNING SIGNS OF PRETERM LABOR    Call your doctor or nurse right away if you notice any of these symptoms: Change in type (watery, mucus, or bloody) of vaginal discharge Increase in amount of discharge Pelvic or lower abdominal pressure Constant, low, dull backache Mild abdominal cramps, with or without diarrhea Regular or frequent contractions or uterine tightening, often painless Ruptured membranes (your water breaks with a gush, or sometimes even a trickle of fluid)

 

    Preterm labor can be diagnosed only by finding changes in the cervix when you are having regular contractions.  This means your doctor will have to examine you.  To help diagnose preterm labor your doctor may use the following tests: 

	Fetal monitoring.  These tests are used to record the heartbeat of the fetus and contractions of your uterus.
	Ultrasonography.  This exam may be used to measure the length of the cervix and estimate the size, age, and position of the fetus.  You may be watched for a time and then examined again to see whether your cervix changes.
	Fetal fibronectin.  This test is used to measure the amount of a certain protein that help predict the risk of preterm delivery.

      You also may have a pelvic exam and tests to look for infections of the vagina or cervix.

 

WOMEN AT RISK

     Preterm labor can occur without warning.  Some women are at greater risk for preterm labor than others.  Women who have little or no prenatal care and those who have had a preterm labor before are at increased risk.  A number of other factors have been linked to preterm labor.  For instance, too much amniotic fluid in the sac that surrounds the baby is a risk factor.  Problems with the placenta or a certain birth defect also increase the risk.  Certain health factors also may be linked to an increased risk for preterm birth:

 

	Short cervical length as measured by ultrasonography
	Increased amounts of the protein fetal fibronectin in vaginal discharge

      If you are at risk for preterm labor or preterm delivery, you may be advised to take certain steps to help prevent preterm birth.  These steps may involve:

 

	Changing your lifestyles ( smoke cigarettes, use drugs,  or are underweight)
	Having more frequent visits with your doctor
	Learning how to check your contractions

      If you are at risk for preterm labor, be sure to get early prenatal care.  You  may need to see your doctor more often for exams and tests.  Smoking cigarettes and using certain illegal drugs, such as cocaine, increase the risk of preterm birth.  Women who have had a previous preterm delivery may be given progesterone, a hormone to help prevent another preterm delivery.

      In many cases, women at risk for preterm labor do not have to take leave from their jobs.  However, you may be advised to avoid heavy lifting or other hard or tiring tasks during pregnancy.  If you take childbirth preparation classes, tell the teacher you are at risk for preterm labor.  he or she may advise you to skip certain classes.  Women at risk also may be advised to cut down on travel.  Ask your doctor about these and other changes you may need to make in your daily routine.  If you have a history of preterm labor or have signs of preterm labor, you may wonder about having sex during pregnancy.  many women worry that the uterine contractions that often follow sex and orgasm will lead to preterm labor.  Although in most cases the contractions stop, these are natural and real concerns that should be discussed with both your partner and your doctor.  You may be advised to restrict sexual activity or to monitor yourself for contractions after sex. 

 

 

MONITORING FOR CONTRACTIONS

     After about 20 weeks of pregnancy, you may be asked to monitor yourself for signs of uterine activity or tightening.  To monitor yourself, lie down on your side and gently feel the entire surface of your lower abdomen with your fingertips.  You are feeling for a firm tightening over the surface  of your uterus.  In most cases, these feelings of tightening are not painful.  if you feel contractions, keep monitoring for an hour.  Keep track of when each contraction starts and ends and the total number that occur in 1 hour.  having some uterine activity before 37 weeks of pregnancy is normal.  If your contractions occur 4 times every 20 minutes or you have 8 contractions in an hour, you need to call your doctor right away.  You may be in preterm labor.  You should contact your doctor or nurse each time you have 8 or more contractions per hour, unless he or she advised otherwise. 

 

 

TREATMENT

     Sometimes contractions can be stopped for at least 48 hours.  Other times, the baby must be delivered.  Your doctor may try to stop labor if:

	It is detected early enough
	You and your baby are not in danger from infection, bleeding, or other complications

     You may be given medications called tocolytics that stop contractions.  As with all medications, tocolytics can  have side effects.  Each woman responds in her own way.  Talk to your doctor about the possible side effects that your medication can cause.  If it looks as though you may have the baby early, you may be given a medication called corticosteroid.  This substance crosses the placenta and helps the baby's lungs mature and increases the baby's chance to live.  Studies suggest that corticosteroids are most likely to help your baby when given between 24 and 34 weeks of pregnancy.  You may be able to go home if you are not really in preterm labor or if labor is stopped, or you may need to stay in the hospital for a while.  This depends on what the doctor's exam reveals.  If you have had preterm labor, your doctor may suggest limits on activity.  The type of activity limits can vary.

 

PRETERM DELIVERY

     Sometimes preterm labor may be too far along to be stopped, or there may be reasons that the baby is better off being born, even if it is early.  These can include:

	Infection
	High blood pressure
	Bleeding
	Signs that the fetus may be having problems

      Many preterm babies are tiny and fragile.  The baby may need special medical care to breathe, eat, keep warm, and treat any health problems that may arise.  You or your baby may be moved to a different hospital that can provide this type of care.  The care your baby needs depends on how early he or she is born.  Preterm babies can have physical and mental disabilities that can be long-term, such as abdominal problems and problems with breathing.  Babies born before 32 weeks of pregnancy are the most likely to have health problems.  Preterm babies may not be ready to live on their own.  They may be cared for in a neonatal intensive care unit (NICU) for week and sometimes months.  Preterm babies often are kept in an incubator to keep them warm.  They are cared for by specially trained nurses and doctors.  Today, with special NICU care, even very early, tiny babies have a chance of survival. 

 

 

FINALLY...

The exact cause of preterm labor are not known.  However, there are things you can do to have  a healthy pregnancy:

	Get regular prenatal care
	Eat healthy foods and do not skip meals
	Lead a healthy lifestyle
	Be alert to signs of preterm labor
	Follow your doctor's advice

 

   

ACOG PATIENT EDUCATION