how accurate is an ultrasound in determining age of fetus
Ultrasound uses the size of the fetus to determine the gestational age (the time elapsed since the the first day of the last menstrual period). The accuracy of the ultrasound estimate of the gestational age varies according to the gestational age.Ultrasound measurement of the embryo or fetus in the first trimester (up to and including 13 6/7 weeks of gestation) is the most accurate method to establish or confirm gestational age [24].ltrasound uses the size of the fetus to determine the gestational age (the time elapsed since the the first day of the last menstrual period). The accuracy of the ultrasound estimate of the gestational age varies according to the gestational age.