What is the range of weeks for preterm births?

The range of weeks defined for preterm births is from 20 weeks up to 37 completed weeks of gestation. Preterm birth is classified as any birth that occurs before 37 weeks, as this timeframe indicates a higher risk of complications for the infant, including developmental issues and health problems. A baby is considered full term if born between 37 weeks and 42 weeks, which is why the other options fall outside the defined range for preterm gestation. Births before 20 weeks are classified as miscarriages or stillbirths rather than preterm, while the periods from 37 weeks onwards refer to full-term and late-term pregnancies, which do not involve preterm classifications.