Preterm Labor - Exams and Tests

Exams and Tests

If you have symptoms of preterm labor, both you and your fetus will be examined and monitored.

For the mother

You will be examined for tenderness in your uterus. Your temperature, pulse, and rate of breathing will be checked as well. Depending on the nature of your symptoms, you may have one or more exams or tests, including:

• A vaginal exam, to find out whether the contractions have begun to open (dilate) or thin (efface) your cervix.
• A vaginal smear, which may be collected to check for:
  • Infection, with a vaginal culture. Disease-causing organisms in the vagina can cause uterine infection, triggering preterm labor and serious infection in the newborn.
  • Amniotic fluid, which shows that the amniotic sac has broken.
  • Fetal fibronectin, the absence of which indicates with 99% certainty that you are not in preterm labor.¹⁰ This test is not useful for actually predicting preterm labor and is not used in all labor and delivery units. It is done before a pelvic exam to reduce the risk of a false-positive result.

Other tests that may be done to check for infection include:

• A complete blood count (CBC), using a blood sample.
• A urinalysis and urine culture, using urine samples.

If an infection is present, you may be treated with antibiotics.

For the fetus

• Your fetus's health is checked using electronic fetal heart monitoring, which records fetal heartbeats. Fetal monitoring also checks, records, and times the mother's contractions and shows how the fetus's heart rate reacts to each uterine contraction.
• A fetal ultrasound test may be used to:
  • Find out whether more than one fetus is in the uterus.
  • Estimate the age, weight, and position of the fetus.
  • Locate and check the condition of the placenta.
  • Check the length of the cervix. A short cervix is a sign that preterm labor may be likely to happen.
• Amniocentesis is sometimes used to take amniotic fluid from the uterus. This test is most commonly used to test the amniotic fluid for:
  • Signs of infection.
  • Substances that show whether the fetus can breathe without assistance, in case of premature birth.

All of this information can help you and your doctor or nurse-midwife decide whether to treat premature labor and delay the birth or allow premature labor to continue and manage any complications that might occur.