Crown Rump Length: Gestational age = 6 weeks plus (CRL x days).
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).
It is this black space that you will see measured during the ultrasound scan.Currently the most accurate non invasive test for detecting Down syndrome during pregnancy is the measurement of the nuchal translucency with an ultrasound between 11 to 14 weeks of pregnancy.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.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.
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 top line represents the skin and bottom one, represents the nasal bone.