Preterm labor occurs between the 20th and 37th week of pregnancy. This labor includes both uterine contractions and cervical changes.
A full-term pregnancy lasts 38-42 weeks but preterm labor can lead to early delivery. Infants born before 37 weeks are considered premature.
In most cases, the cause is of preterm labor is unknown.
Some preterm labor is associated with preterm premature rupture of membranes (PPROM). PPROM is the rupture of both the amniotic sac and chorion membranes. It generally occurs at least one hour before labor begins.
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The chance of preterm-labor is greatest in women under the 18 years or over 35 years. Other maternal factors that may increase the chance of preterm labor include:
Low socioeconomic status
prenatal care and social support
Being underweight or
before becoming pregnant
Physical, sexual, or emotional abuse
depression or anxietyDiabetesHigh blood pressureClotting disordersHormonal imbalanceCertain medications to treat health problems or exposure to diethylstilbestrol (DES)SmokingIllicit drug useAlcohol use
Pregnancy complications that may increase your risk of preterm labor include: Pre-eclampsia
Placental abruptionPremature rupture of the membranesCarrying more than one babyVaginal bleeding after 16 weeks, or during more than one trimesterInfection in the cervix, uterus, vagina, or urinary tract including STDs
Being pregnant with a single fetus after
in vitro fertilization (IVF)Presence of a retained intrauterine deviceIncompetent cervixToo much or too little fluid surrounding the baby
Surgery on your abdomen during pregnancy
Amniotic fluid infectionIntrauterine fetal deathIntrauterine growth delayBirth defects in the baby
Other factors associated with an increased chance of preterm labor include: History of one or more spontaneous second-trimester abortionsLess than six months between giving birth and the beginning of the next pregnancyA previous preterm birthUterine fibroidsAbnormally shaped uterus
Symptoms may include:
Abdominal pain that feels something like menstrual crampsDull pain in the lower backPressure in the pelvis and tightening in the thighsVaginal bleeding or spotting, or watery discharge
Your doctor will ask about your symptoms and medical history. A physical exam will be done. Your doctor may recommend tests to check your cervix and membranes have ruptured. An ultrasound will help your doctor see internal structures and the baby.
Fluids in the cervix will also be tested for sign of labor progression. A tocometer may be placed to help monitor contractions.
Treatment will depend on your baby's development, especially the growth of the lungs. If your doctor believes the baby is ready, the labor may be allowed to continue. If the baby is not ready to be delivered, your doctor may try to stop the labor. Stopping labor is a complicated process and may not always work. Some treatment options may include: Tocolytics—may delay labor for a few days Corticosteroids—to help the baby's lungs develop Antibiotics—if an infection is suspected or present
To help reduce your chance of preterm labor, take the following steps:
Get the proper prenatal care throughout your entire pregnancy.
Eat a healthy, balanced diet with plenty of fruits, vegetables and whole grains.Avoid smoking, alcohol, and drugs.Keep chronic diseases under control.Stay active during your pregnancy. Your doctor can give you exercise guidelines that are right for you.If you are at high-risk for premature birth, talk to your doctor about progesterone therapy.
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Last reviewed April 2013 by Andrea Chisholm, MD; Brian Randall, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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