• (preterm) Gestation that is less than 37 wks. and 0 days' gestational age.
  ACC/AHA Clinical Data Terminology
  American College of Cardiology and American Heart Association , 2020
• (preterm birth) Birth at less than 37 weeks and 0 days gestation.
  NICHD Pediatric Terminology
  U.S. National Cancer Institute, 2021
• (preterm birth) Birth when a fetus is less than 37 weeks and 0 days gestational age.
  NCI
  U.S. National Cancer Institute, 2021
• CHILDBIRTH before 37 weeks of PREGNANCY (259 days from the first day of the mother's last menstrual period, or 245 days after FERTILIZATION).
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2025
• The birth of a baby of less than 37 weeks of gestational age.
  Human Phenotype Ontology (HPO)
  The Human Phenotype Ontology Project, 2025
• (premature delivery) A disorder characterized by delivery of a viable infant before the normal end of gestation. Typically, viability is achievable between the twentieth and thirty-seventh week of gestation.
  Common Terminology Criteria for Adverse Events
  U.S. National Institutes of Health, 2021
• Prematurity refers to the broad category of neonates born at less than 37 weeks' gestation. Although the estimated date of confinement (EDC) is 40 weeks' gestation, the World Health Organization (WHO) broadened the range of full term to include 37-42 weeks' gestation.
  Medscape
  WebMD, 2025
• A premature birth is a birth that takes place more than three weeks before the baby's estimated due date. In other words, a premature birth is one that occurs before the start of the 37th week of pregnancy.
  Mayo Clinic
  Mayo Foundation for Medical Education and Research, 2025
• Premature birth, in humans, any birth that occurs less than 37 weeks after conception. A full-term pregnancy lasts anywhere from 37 to 42 weeks. The worldwide incidence of premature birth ranges between 6 and 11 percent. In the United States prematurity occurs in about 7 to 9 percent of pregnancies...
  Encyclopedia Britannica
  Encyclopedia Britannica, Inc., 2025