You do not need to have a full bladder, a moderately filled bladder is needed for a proper examination.
Most parents look forward to their scan because it gives them the first glimpse of their baby.
A scan maybe ordered when an abnormality is suspected on clinical grounds.
Otherwise a scan is generally booked in the first trimester to confirm pregnancy, exclude ectopic or molar pregnancies, confirm cardiac pulsation and measure the crown to rump length for dating.
For example, a CRL of 23 mm would correspond to a gestational age of 9 weeks and two days (6 weeks plus 23 days = 9 weeks and 2 days).
If the nasal bone is visible at the scan then this will reduce the chance of your baby having Down's syndrome.
The view of the nasal bone should show three distinct lines: The first two lines, are horizontal and parallel to each other, resembling an 'equal sign'.
The fluid collection is however increased in many fetuses with Down's syndrome and many other chromosomal abnormalities.
It is called a 'translucency' because on ultrasound this appears as a black space beneath the fetal skin.