Knowing about twins early is also useful if you want to have screening for Down's syndrome.This is because blood tests for Down's syndrome are not very accurate if you are having more than one baby.It may show a very minor problem, or something which may get better on its own. As with all screening tests, there can be false positive and false negative results. Then the circumference of the head becomes the best way to measure your baby Nuchal translucency can be measured from 11 to 14 weeks to estimate the risk of Down's syndrome and other chromosomal abnormalities. Some hospitals offer a nuchal translucency ultrasound to all women at 11 to 14 weeks, but this isn't available everywhere. [Epub ahead of print, accessed April 2009] Gray JAM, Ward P. National Down's Syndrome Screening Programme for England: a handbook for staff. Sometimes having an ultrasound can cause unnecessary worry. Kettering: National Down's Syndrome Screening Programme.
Your baby's head, limbs, hands and feet, and some organs can be seen, and - though looking for abnormalities isn't the purpose of the ultrasound - some major problems can be seen at this early stage.Instead, you will be offered a nuchal translucency ultrasound.This measures a collection of fluid under the skin at the back of a baby's neck. Nearly all ultrasound after 10 weeks can be done through your tummy, and most units ask you to come with a full bladder.But if thin patient, experienced operator of the ultrasound and good views it can be very accurate. Otherwise, you might want to check the dates you provided. Read more First trimester ultrasound is accurate within 5-7 days.. Au/services/pregnancy-ultrasound-5-17-weeks-dating-and-viability. The fact that these 2 ultrasounds agree means that you have very accurate dating. Also if you are uncertain about your LMP, most OB's will use that early US. Read more 14 week ultrasound is on the cusp between first and 2nd trimester. (if the number did not already have the 2 weeks added on, then the number would be the "age of the fetus", which is 2 weeks less than the "number of weeks pregnant") ...There is no test that can date conception more accurately than a 1 week window. First trimester ultrasound usually accurate to 3-5 days. So at 14 weeks I would doubt the dates would be 2w3d off. For example, about one in 20 women will appear to be at high risk from the nuchal translucency ultrasound to assess the risk of Down's syndrome, but most of these babies will turn out not to have Down's syndrome. Now that you know all about ultrasounds scans, test your new-found knowledge by taking our quiz!