Fetal age is the actual age of the fertilized egg. Gestation age is the date from the end of the last menstrual cycle, an increase of roughly two more weeks.
Fetal age is the age of the fetus, starting counting at conception. Gestation age begins at the first day of the last period before conception, usually two weeks before conception.
Gestational age is used most commonly when referring to pregnancy, and is determined by the mother's last menstrual period. Fetal age refers to the actual age of the fetus.
Fetal age is calculated from conception, which occurs approximately 14 days after the first day of the woman's last menstrual period (LMP). Gestational age is calculated from her LMP.
