With many years of experience, you will get the most accurate information about your pregnancy. This is normally done during the first trimester to confirm the pregnancy and estimate how long you’ve been pregnant. The most common use of ultrasound in early pregnancy, is to calculate the gestational age of your baby, so you will have a more accurate date. At this Ultrasound, you may see the GS, Fetal pole, HB and even the Embryo, which develops alongside the yolk sac.