1st Trimester Scans

1st trimester scans will be done to:

  1. Confirm a normal intrauterine pregnancy
  2. Exclude extra-uterine pregnancy or miscarriage
  3. Determine the fetal age by measuring the length of the embryo (this will establish the dating of the pregnancy)
  4. Determine the baby’s heart rate
  5. Look for multiple pregnancies (twins, triplets, etc.)
  6. Identify problems of the placenta, uterus, cervix, and ovaries

How accurate is pregnancy dating?

A measurement of the length of the embryo at 7-11 weeks gestation is accurate to within about 3 days. Beyond this time the accuracy reduces due to flexion (bending) of the fetus and individual’s growth variance.