What are the causes and risk factors for preterm labor?

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Last updated: June 22, 2025View editorial policy

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From the Research

Preterm labor is a complex condition with multiple causes and risk factors, and the most significant predictors include previous preterm birth, infections, placental problems, uterine abnormalities, and cervical insufficiency, as well as lifestyle and demographic factors, as identified in the study by 1. The causes and risk factors for preterm labor are multifaceted and can be categorized into several key areas, including:

  • Medical conditions, such as infections (urinary tract, vaginal, or intrauterine), placental problems (placenta previa, placental abruption), uterine abnormalities, and cervical insufficiency, which are supported by the findings of 1 and 2
  • Maternal health factors, including high blood pressure, diabetes, obesity, and autoimmune disorders, as noted in the study by 1
  • Lifestyle factors, such as smoking, alcohol consumption, drug use, poor nutrition, and high stress levels, which are highlighted in the research by 1 and 3
  • Demographic factors, including maternal age extremes (under 17 or over 35), African American race, and low socioeconomic status, as identified in the study by 1 and 4
  • Environmental exposures, such as pollution, certain chemicals, and excessive physical demands, which are mentioned in the research by 2 and 3 Understanding these risk factors is crucial for healthcare providers to identify high-risk pregnancies and implement preventive measures, such as progesterone supplementation, cervical cerclage, or more frequent monitoring, as recommended by 1 and 3. The study by 1 provides the most recent and comprehensive evidence on the causes and risk factors for preterm labor, and its findings should be prioritized in clinical practice. Key risk factors for preterm labor, as identified by 1, include:
  • Intercourse during the previous week
  • Multipartite
  • Short time from last delivery
  • Preeclampsia
  • Fetal anomaly
  • Rupture of membranes
  • Hypertension
  • Amniotic fluid leak These risk factors should be carefully assessed and managed to reduce the risk of preterm labor and improve outcomes for mothers and babies.

References

Research

Preterm labor: one syndrome, many causes.

Science (New York, N.Y.), 2014

Research

[Preterm labor: pathophysiology, risk factors and outcomes].

Journal de gynecologie, obstetrique et biologie de la reproduction, 2002

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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