London Ultrasound Centre logo

What is Down Syndrome?

At a glance

What is Down Syndrome?

Down Syndrome is a genetic disorder that is caused by the presence of an extra copy of chromosome 21.

Anyone can give birth to a baby with Down Syndrome and the chances of have a Down’s baby increase with the age of the mother.

Usually it is not inherited and a baby can be affected even if there is no previous history of the condition in your family.

All mothers in the UK should be offered Down Syndrome screening through the NHS although not all hospitals currently offer the more accurate combined test.

At the London Ultrasound Centre we offer the more accurate Non-Invasive Prenatal Test.

What is a screening test?

A screening test determines the chances of you giving birth to a baby with Down Syndrome (chromosome 21).

It cannot tell if your baby has the disorder, but it calculates your personal risk factor.

It will also reveal information about your risk of other common chromosome anomalies, such as Edward’s Syndrome (chromosome 18) and Patau Syndrome (chromosome 13).

How to understand the results

All screening tests have a clinically agreed figure that is the border between high and low risk.

If you are high risk your result will be described as ‘screen positive’ and you will be offered a diagnostic test to give you a definite answer.

It is worth knowing that most screen positive results come out as false once the diagnostic test is complete.

If your Down Syndrome screening produces a ‘screen negative’ low risk result you will not be offered a diagnostic test, however, that does not mean you cannot have one if you want.

A very small number of low risk screenings will not detect a baby that has Down Syndrome.

Should I have a diagnostic test?

It’s a personal choice and rests with you and your partner, rather than your doctor.

But, like all medical procedures, the diagnostic test carries some risk, so you will have to consider the likelihood of having a Down Syndrome baby against the risk of miscarriage by having an invasive procedure.

Down Syndrome tests at the London Ultrasound Centre

We offer newest most accurate method of Down Syndrome screening:

We can also provide the older style of tests:

If you receive a high risk result we offer the following diagnostic tests:

Our expert team is also here to support your choice of Down Syndrome screening or diagniostic testing with further advice and counselling.

Age risk chart

Download a copy of the Down Syndrome age risk chart.