Risk Factors for Preterm Labor and Delivery

A risk factor is something that raises a person's chances of getting a disease or health problem. A woman can have preterm labor with or without the risks below. The more risks a woman has, the greater the chances are.

Preterm labor is more common in women who:

  • Are Black
  • Are pregnant with more than 1 baby
  • Have used assisted reproductive technologies
  • Are under the age of 16 years old

Some things that may raise the risk are:

  • Prior premature birth
  • Problems with the cervix, such as a cervix that is weak or short
  • Certain infections, such as bacterial vaginosis or chlamydia
  • Tobacco or alcohol use
  • Taking certain medicines, such as steroids
  • Exposure to pollutants
  • Mental health problems, such as depression or anxiety
  • Problems with the placenta or uterus, such as too much fluid in the womb
  • Vaginal bleeding
  • Birth defects in the fetus


American College of Obstetricians and Gynecologists’ Committee on Practice Bulletins—Obstetrics. Practice Bulletin No. 171: Management of Preterm Labor. Obstet Gynecol. 2016 Oct;128(4):e155-64, reaffirmed 2018.
Preterm labor and birth: overview. National Institute of Child Health and Human Development website. Available at: https://www.nichd.nih.gov/health/topics/preterm/Pages/default.aspx. Accessed July 30, 2020.
Preterm labor and birth. The American College of Obstetricians and Gynecologists website. Available at: https://www.acog.org/patient-resources/faqs/labor-delivery-and-postpartum-care/preterm-labor-and-birth. Accessed July 30, 2020.
Preterm labor. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/preterm-labor. Accessed July 30, 2020.
Who is at risk for preterm labor and birth? National Institute of Child Health & Human Development website. Available at:
...(Click grey area to select URL)
Accessed July 30, 2020.
Last reviewed March 2020 by EBSCO Medical Review Board Beverly Siegal, MD, FACOG
Last Updated: 2/26/2021

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