Full term pregnancy, also known as aterm pregnancy, is defined as the period when the baby is born between 39 weeks and 0 days and 40 weeks and 6 days of gestation. This means the pregnancy reaches full term around 39 weeks of gestational age. This definition has been updated from an older, broader range where any birth from 37 weeks to 42 weeks was considered term. The change was made because research shows that babies born before 39 weeks may still have developmental challenges, especially with breathing, feeding, and temperature regulation. Babies born full term (39 to 40 weeks) have the best chances of healthy development with more mature organs such as lungs, liver, and brain. To summarize key time frames related to term pregnancy:

• Early term: 37 weeks 0 days to 38 weeks 6 days
• Full term: 39 weeks 0 days to 40 weeks 6 days
• Late term: 41 weeks 0 days to 41 weeks 6 days
• Postterm: 42 weeks 0 days and beyond

Waiting until at least 39 weeks for delivery, if the pregnancy is healthy, is recommended for the best outcomes for both mother and baby.