Dating for only 2 weeks
Charts have been developed for this purpose, but some simple rules of thumb can also be effectively used.
From 6 to 11 weeks gestational age, the fetal CRL grows at a rate of about 1 mm per day.
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.
The baby will be measured, and the anatomy examined in detail.
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 crown rump length is a universally recognized term, very useful for measuring early pregnancies.
The CRL (see image above between the two white marked 1) is highly reproducible and is the single most accurate measure of gestational age.
The test cannot be performed outside this time frame as certain features that need to be seen on the scan are not present.
This test results in a 9095% detection rate of pregnancies that may be at an increased risk of carrying a genetical problem such as Downs Syndrome.