Dating scan nuchal scan
Accuracy of CRL after 12 weeks in predicting gestational age diminishes and is replaced by measurement of the width of the fetal head (biparietal diameter or BPD).
The nuchal translucency (also spelled nucal translucency) is a collection of fluid beneath the fetal skin in the region of the fetal neck and this is present and seen in all fetuses in early pregnancy.
If you are unsure of your period dates or have an irregular cycle, we suggest that you contact your doctor, midwife or health care provider as early as possible to arrange for a dating scan.
There is no hard and fast rule for the number of scans you should have during pregnancy.
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 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.The first Trimester Scan, is Scans are usually performed by a doctors, midwives or radiographers who are specially trained in ultrasound, and are known as sonographers. The amount of liquor (amniotic fluid), the position and appearance of the placenta and a detailed scan of the baby itself.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.