Below are scan pictures taken during the early weeks of pregnancy. Measurements taken at these early scans will help to; confirm a pregnancy, date the. Crown–rump measurements at 6–10 weeks are accurate in assigning gestational age with a 95% confidence interval [CI] ± 3–5 days. and 2 of Pregnancy. There's no ultrasound image of your baby-to-be for weeks 1 and 2. Your pregnancy due date is calculated using the first day of your last menstrual period (LMP). Obviously you Week 5 of Pregnancy. Fetal Size: 1/18 .