Preterm labor occurs when regular contractions begin to open your cervix before 37 weeks of pregnancy. A full-term pregnancy should last about 40 weeks.
For some women, the signs and symptoms of preterm labor are unmistakable. For others, they're more subtle. During pregnancy, be on the lookout for:
• Regular or frequent contractions — a tightening sensation in the abdomen
• Constant low, dull backache
• A sensation of pelvic or lower abdominal pressure
• Mild abdominal cramps
• Vaginal spotting or bleeding
• Watery vaginal discharge (water breaking) — in a gush or a trickle
• A change in vaginal discharge
To help diagnose preterm labor, your health care provider will document your signs and symptoms. If you're experiencing regular, painful contractions and your cervix has begun to soften, thin and open before 37 weeks of pregnancy, you'll likely be diagnosed with preterm labor.
Tests and procedures to diagnose preterm labor include:
• Pelvic exam. Your health care provider might evaluate the firmness and tenderness of your uterus and the baby's size and position.
• Ultrasound. An ultrasound might be used to measure the length of your cervix and determine your baby's size, age, weight and position in your uterus.
• Uterine monitoring. Health care provider might use a uterine monitor to measure the duration and spacing of your contractions.
• Lab tests. Your health care provider might take a swab of your vaginal secretions to check for the presence of certain infections and fetal fibronectin
• Maturity amniocentesis. Health care provider might recommend a procedure in which amniotic fluid is removed from the uterus (amniocentesis) to determine your baby's lung maturity