Definition: Gestational age is the age of a fetus or baby counted from the first day of the mother’s last menstrual period. A normal pregnancy lasts between 38 and 42 weeks. Infants who are born before 37 weeks gestation are considered premature; infants who are born after 42 weeks gestation are considered postmature.
When parents of premature babies are comparing their babies to charts of normal infant development, they should use their gestational age as well as their birth age. A baby born at 30 weeks (10 weeks early) can be expected to crawl 10 weeks later than a baby born at 40 weeks gestation.
