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; 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.
Are You at Risk for Having Premature Labor?
The chance of preterm-labor is greatest in women under 18 years or over 35 years. Other maternal factors that may increase the chance of preterm labor include:
- Low socioeconomic status
- Lack of prenatal care and social support
- Being underweight or before becoming pregnant
- Physical, sexual or emotional abuse
- Severe or
- Clotting disorders
- Hormonal imbalance
- Certain medications to treat health problems or exposure to diethylstilbestrol (DES)
- Alcohol use
Pregnancy complications that may increase your risk of preterm labor include:
- Placental abruption
- Premature rupture of the membranes
- Carrying more than one baby
- Vaginal bleeding after 16 weeks or during more than one trimester
- Infection in the cervix, uterus, vagina or including sexually transmitted diseases (STDs)
- Being pregnant with a single fetus after in vitro fertilization (IVF)
- Presence of a retained intrauterine device (IUD)
- Incompetent cervix
- Too much or too little fluid surrounding the baby
- Surgery on your abdomen during pregnancy
- Amniotic fluid infection
- Intrauterine fetal death
- Intrauterine growth delay
- Birth defects in the baby
Other factors associated with an increased chance of preterm labor include:
- History of one or more spontaneous second-trimester abortions
- Less than six months between giving birth and the beginning of the next pregnancy
- A previous preterm birth
- Uterine fibroids
- Abnormally shaped uterus
- Previous bariatric surgery
- Procedures to remove abnormal cervical cells
Are You Having Preterm Labor?
Symptoms may include:
- Abdominal pain that feels something like menstrual cramps
- Dull pain in the lower back
- Pressure in the pelvis and tightening in the thighs
- Vaginal bleeding or spotting or watery discharge
To determine what's happening, your doctor may:
- Check if your cervix and membranes have ruptured
- Conduct an ultrasound
- Test fluids in the cervix for signs of labor progression
- Monitor contractions with a tocometer
When Preterm Labor Happens
If your doctor believes the baby is ready to be delivered, the labor may be allowed to continue.
If the baby is not ready to be delivered, your doctor may try to stop the labor and use the following:
- Tocolytics — may delay labor for a few days
- Corticosteroids — to help the baby's lungs develop
- Antibiotics — if an infection is suspected or present
Stopping labor is a complicated process and may not always work.
Preventing Premature Birth
To help reduce your chance of preterm labor, take the following steps:
- Get proper prenatal care
- Eat a healthy, balanced diet with plenty of fruits, vegetables and whole grains — consider adding fish
- Avoid smoking, alcohol and drugs
- Keep chronic diseases under control
- If you are at high-risk for premature birth, talk to your doctor about progesterone therapy
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Content was created using EBSCO’s Health Library. Edits to original content made by Rector and Visitors of the University of Virginia. This information is not a substitute for professional medical advice.