A full-term pregnancy typically lasts for 40 weeks. This means that from the first day of the woman's last menstrual period, it takes about 40 weeks or 280 days for the baby to develop and be ready for birth.
During this time, the baby goes through many stages of development, starting as a tiny cell and growing into a fully-formed baby. The last few weeks of pregnancy are especially important for the baby's growth and development, as important organs like the brain and lungs continue to mature.
While some babies may be born a few weeks early or a few weeks late and still be healthy, a full-term pregnancy is generally considered to be the healthiest for both the baby and the mother.