Preterm Labor



The cause of preterm labor is not always known. Sometimes it is caused by preterm premature rupture of membranes (PPROM). This is when the amniotic sac breaks before 37 weeks and labor has not started within 1 hour.

Amniotic Sac
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Risk Factors

Preterm labor is more common in women who:

  • Are Black
  • Are pregnant with more than one baby
  • Used assistive reproductive technology to become pregnant
  • Are under 16 years of age

Some things that may raise the risk are:

  • Prior premature birth
  • Problems with the cervix
  • Certain infections
  • Substance use disorder
  • Alcohol use disorder
  • Mental health problems, such as depression or anxiety
  • Problems with the placenta or uterus
  • Vaginal bleeding
  • Birth defects in the fetus



Problems may be:

  • Belly cramps with or without diarrhea
  • Watery or bloody vaginal discharge
  • An increase in discharge
  • Dull pain in the lower back
  • Pressure in the pelvis and tightening in the thighs


The doctor will ask about symptoms and past health. An exam will be done. This is often enough to make the diagnosis.



Treatment will depend on the baby's growth, especially the lungs. Labor may be allowed to go on in a baby that is more developed. The doctor may try to stop labor in a baby that is not developed enough.

Some ways this may be treated are with:

  • Tocolytics to try to delay labor for a few days
  • Corticosteroids to help the baby's lungs grow
  • Antibiotics to treat an infection


Preterm labor cannot always be prevented. Early and regular prenatal care can help find and treat some problems before they happen.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.