Dating a girl with spina bifida
This is normally less than 2.5mm and when seen increased (greater than 2.5mm, see image on the right) may indicate the baby has Down syndrome or may indicate another chromosomal abnormality. The nuchal translucency test will also check whether your baby has a visible nasal bone.
In the past few years it has been seen that approximately 3 in 4 babies with Down's syndrome do not have a visible nasal bone at the time of the first trimester screening test.
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'.
At the first trimester scan they confirm that the fetus is alive, they assess the gestational age by measuring the crown-rump length and will look for any major problems.
This is a routine ultrasound examination done at 10 to 14 weeks of gestation.
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.
At the first trimester scan they confirm that the fetus is alive, they assess the gestational age by measuring the crown-rump length and will also look for any major problems.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.During the examination, the fetus is seen by abdominal ultrasound.
Occasionally the view is not clear and it may be necessary to perform a vaginal scan.
You will probably be give you a printout of your baby by the sonographer as a keepsake, it is important to remember the main purpose of the scan.