Generally at least 2 scansor ultra sounds are performed during pregnancy. The first is usually to date the age of gestation and the second, to check on the development of the baby’s organs. The difference in the Estimated Due date calculated from your last day of your menses and doctor’s scan may be due to the regularity of your menstruation. It is reasonable to infer that your doctor will go by the EDD that is most closely correlated to the growth of your uterus in terms of size and height throughout your pregnancy.
