Vaginal Exam for Preterm Labor
If you have symptoms of preterm labor, your doctor or nurse-midwife may examine you by feeling your cervix . If your contractions continue over a period of hours, you may be examined periodically to see whether your cervix is opening (dilating) or thinning (effacing).
These exams allow your health professional to:
- Find out how much your cervix has opened and thinned.
- Find out how far the baby has moved down the birth canal (station).
- Check for fluid leaking from your vagina using a sterile speculum . If fluid is present, it will be tested to determine whether it is amniotic fluid , which is a sign that your amniotic sac has ruptured.
Why It Is Done
Vaginal exams are done when a pregnant woman has:
- Uterine contractions that may have changed her cervix and may be preterm labor. The cervix may open and thin without strong or painful contractions.
- Unusual pelvic pressure or back pain.
- Vaginal bleeding.
Preterm labor is diagnosed when a woman who is 20 to 37 weeks pregnant has uterine contractions and her cervix has changed, as seen with a vaginal exam.
Preterm labor is not diagnosed if contractions are occurring but the cervix is not becoming thinner or more dilated (open).
What To Think About
When a vaginal exam is not done to assess for preterm labor
When the amniotic membranes rupture early (preterm premature rupture of membranes, or pPROM), sterile speculum exams are kept to a minimum, and digital exams are avoided. This is meant to reduce the risk of infecting the uterus and fetus.
When the placenta is known to be overlapping or covering the cervix ( placenta previa ), vaginal exams are completely avoided. Disturbing the placenta can trigger bleeding.