The age of a fetus, calculated from the mother’s last period to the date of birth.
The age of a fetus still in the uterus or of a premature newborn, indicating the number of weeks of development, usually measured by physicians as the number of weeks from the beginning date of the mother’s last menstruation. Gestational age is important because premature infants are less fully developed; and the younger they are, the more vulnerable they are to certain kinds of disorders. Sleep apnea, for example, occurs in about 35 to 50 percent of premature infants, but it occurs among nearly 90 percent of those who are less than 29 weeks in gestational age (as opposed to the normal 40 weeks).
Age of a fetus or newborn, usually expressed in weeks since the onset of the mother’s last menstrual period.
The age of an embryo or fetus as timed from the date of onset of the last menstrual period.
The approximated chronological age of a fetus, denoted in weeks, reckoned from the onset of the most recent ordinary menstrual cycle.