Preterm labor can affect any pregnancy and many women who have preterm labor have no known risk factors. Many factors have been associated with an increased risk of preterm labor, however, including:

  • Previous preterm labor or premature birth, particularly in the most recent pregnancy or in more than one previous pregnancy
  • Pregnancy with twins, triplets or other multiples
  • Certain problems with the uterus, cervix or placenta
  • Smoking cigarettes or using illicit drugs
  • Certain infections, particularly of the genital tract
  • Some chronic conditions, such as high blood pressure and diabetes
  • Being underweight or overweight before pregnancy, or gaining too little or too much weight during pregnancy
  • Stressful life events, such as the death of a loved one
  • Red blood cell deficiency (anemia), particularly during early pregnancy
  • Too much amniotic fluid (polyhydramnios)
  • Pregnancy complications, such as preeclampsia
  • Vaginal bleeding during pregnancy
  • Presence of a fetal birth defect
  • Little or no prenatal care
  • An interval of less than six months since the last pregnancy

Also, having a short cervical length or the presence of fetal fibronectin — a substance that acts like a glue between the fetal sac and the lining of the uterus — in your vaginal discharge has been linked to an increased risk of preterm labor.

While some past research suggested that gum disease might be linked with premature birth, treatment of periodontal disease during pregnancy hasn't been proved to reduce the risk of premature birth.

Oct. 19, 2016