Nuchal Translucency One of Bay Scans primary roles is to offer Nuchal Translucency (NT) scanning, part of the Down’s syndrome screening service.
Previously women from Lancashire and Cumbria travelled to Leeds, Manchester or even Newcastle to undertake this Combined Ultrasound & Blood analysis test. This will no longer be necessary as the Nuchal Translucency ultrasound scan will now be available at Bay Scan Lancaster. The Bay Scan team appreciate that this can be a time of stress and worry, we will ensure the scan is undertaken in a discreet, sympathetic and professional manner. What is an NT scan?A Nuchal Translucency (NT) scan is an ultrasound scan during which a small amount of fluid behind the babies neck is measured. Babies with Down's syndrome, heart defects and other chromosome abnormalities, often have an increased amount of fluid.
The amount of fluid is therefore related to your babies risk of carrying a chromosome abnormality such as Down’s Syndrome. The higher the measurement on ultrasound, the higher the risk.
During the ultrasound scan we will assess the well being of the baby, and establish accurate dating by measuring the crown rump length (CRL) The combined testThe combined test is a simple and effective method of estimating the risk of your baby having Down's syndrome. The test is non invasive, and is carried out between 11 and 13 weeks 6 days of gestation. When combined, the two tests will detect 90% of babies with Down's syndrome. The risk of other chromosome variations such as Edward's syndrome is also estimated.
The screening test is comprised of the ultrasound scan and a simple blood test.
Substances in the blood such as B-hCG and PAPP-A are analysed.
The blood results, NT measurement and a number of other factors such as the mother's age, weight and length of the baby, are processed by a computer programme and a risk factor is generated.
Most babies are of course perfectly normal, however, any woman regardless of age has a risk of carrying a baby with Down’s syndrome, or other chromosome variations.
The risk of Down’s syndrome does increase with age, for example, a woman aged 30 will carry a risk of 1 in 910, compared to a risk of 1 in 28 at the age of 45. After screening a risk factor that exceeds 1 in 250 is considered screen positive. DiagnosisThe combined test is a screening test and is course not definitive.
The only sure way to discover if your baby has a chromosomal variation such as Down’s syndrome is to undertake a diagnostic test. These tests are done by the NHS.
The tests available are Chorionic Villus Sampling (CVS) or Amniocentesis.
Both are definitive tests, but both are also invasive tests, which carry a small risk of miscarriage.
Booking the combined testYou are able to self refer for the test.
The blood test is usually carried out from 10 weeks, and the ultrasound scan from 11 weeks, up to 13 weeks 6 days( We prefer to do NT scans between 12 weeks and 13 weeks 6 days). The timing of the scan is important, if you are unsure of your dates, it is advisable to have a dating scan. This can be organised through your GP or community midwife. Bay Scan also offer this service on a private basis.
The ultrasound scan will be done in Lancaster by experienced sonographers who are accredited by the Fetal Medicine Foundation (FMF). To book your ultrasound scan :telephone Bay Scan 01524 39603. We can give & send you information and a blood pack if you prefer to have your blood sample sent in advance. If your midwife is taking your booking bloods then she may be prepared to take the NT sample at the same time. Which will save you having two venopunctures. Alternatively, you can have the blood taken at the same time as your scan on a wednesday at Bay Scan. Bay Scan is open all day wednesday, friday and saturdays, but we prefer to do the NT scan on a wednesday, to ensure the blood reaches Leeds the following day & does not get mixed up with weekend or bank holiday mail.
Alternatively you can ring the Leeds Screening Centre on 0113 262 1675 they will offer advice and answer any questions that you may have. They will send you an information and blood sample pack. A blood test can then be arranged, often through your GP or Midwife. Leeds Screening Centre will refer you to Bay Scan for your NT ultrasound scan.
To optimize the ultrasound scan you will be required to drink 1 pint of water, an hour before the scan. The scan will normally take between 15 and 30 minutes. Occasionally the baby may be in such a position, that a measurement cannot be made, in which case an internal scan may be necessary. If your baby is dated at less than 11 weeks, the test will be deferred to the appropriate time. There will be a minimal charge for this dating scan.
Two 6 x 4inch gloss prints of you baby are included with the scan.
The Combined test resultsThe test results will normally be available within 2-5 days. You can contact the Leeds Screening Centre directly for your results. A printed report will also be sent to you. We recommend that you make a copy available to the medical professional managing the care of your pregnancy.
If the test returns a high risk result, for example 1 in 250 or higher, then your consultant obstetrician will advise you on the options available.
The combined test is recommended by the National Screening Committee (NSC) and the Fetal Medicine Foundation (FMF). |
