According to WebMD, the main signs of premature labor are backaches, abdominal cramps and contractions that occur every 10 minutes. Preterm labor may be confused with Braxton Hicks contractions that are common in late pregnancy. The backaches and contractions of preterm labor are much stronger than those associated with normal pains during pregnancy.
WebMD explains that fluid leaking from the vagina, increased vaginal discharge and increased pressure in the pelvic region are signs that preterm labor has begun. Vaginal bleeding associated with these symptoms should be checked by a doctor immediately to determine if preterm labor has begun. Preterm labor may cause flu-like symptoms such as vomiting, nausea or diarrhea. Women who smoke, are overweight, drinking alcohol, doing drugs, are pregnant with twins or are not receiving adequate prenatal care are at risk for preterm labor. Pregnant women with preeclampsia, gestational diabetes or blood clotting disorders are at risk for preterm labor as well.
The Mayo Clinic states that pregnant women before 37 weeks should monitor contractions if they become regular. Minor contractions are normal before 37 weeks, but a regular pattern of four contractions within 20 minutes or eight contractions in an hour could be a sign of preterm labor. Pregnant women should call their doctor to rule out false labor.