At a glance
Looking for the most accurate Down Syndrome screening? Want to avoid the risks associated with diagnostic testing? Have you considered a Non-Invasive Prenatal Test?
An Amniocentesis is an accurate diagnostic test for specific genetic abnormalities in mid to late pregnancy - normally Down Syndrome, Edwards’ and Patau Syndromes. Other tests can be performed at additional cost.
- No GP referral required
- Procedure performed by a highly qualified fetal medicine specialist
- Service not available on the NHS for low risk pregnancies
- Appointments available at short notice
- Convenient central London location
You will receive
- Results in 3 days
- Two-page clinical report, plus genetic results
- 100% accurate gender identification, if you want to know
What we need to know before
To assist with the procedure you will need written confirmation of your blood group. If you don’t have this we can help you arrange a blood test when you book.
What happens with your results?
We will call you 3 days after your appointment to let you know your results.
What is an amniocentesis?
An amniocentesis is a the name give to a medical procedure performed during a pregnancy to take a small sample of fluid from the pregnancy sac. The sample is then analysed in a laboratory to diagnose any genetic abnormalities of your unborn baby.
Because the cells in this fluid come from your baby, genetic analysis of the fluid will give the same results as if the fetus itself were examined.
Why have an amniocentesis?
An amniocentesis is usually offered on the NHS or privately if you have received a high risk result from your Down Syndrome screening, such as the nuchal scan, integrated test or quadruple test. However, you may wish to have an amniocentesis for your own peace of mind.
Even if you have had a high risk result, the choice of whether to have the test or not is up to you.
What does the amniocentesis check for?
The sample will be tested for Down Syndrome, Edward’s Syndrome and Patau Syndrome and will be given a chromosomal analysis to detect disorders such as Klinefelter Syndrome. We will also check for Cystic Fibrosis, at no extra charge, if there is a family history of the condition.
Genetic testing can also be performed for other identifiable problems at an additional charge. These supplementary tests can be included if there is a family history or other children have been born with the condition.
A consultation with one of our fetal medicine specialists will be necessary before proceeding with any of the following tests, and in some instances an appointment with a consultant geneticist will be required:
- Smith-Magenis Syndrome
- Miller-Dieker Syndrome
- DiGeorge Syndrome
- Prader-Willi Syndrome
- Angelman Syndrome
- Wolf-Hirschhorm Syndrome
- Cri du Chat Syndrome
- Langer Giedion Syndrome
- Phelan-McDermid Syndrome
- 15q24 Deletion Syndrome
- 17q21.21 Microdeletion Syndrome
- Analysis of subtelomeric regions of all 46 chromosomes
Amniocentesis can also be used to obtain samples for pre-natal paternity testing.
What happens during an amniocentesis appointment?
Most of the appointment time is taken up with preparation and counselling, allowing you time to ask the fetal medicine specialist any questions and to sign our consent form which will be fully explained to you. The actual amniocentesis only takes one or two minutes and is usually completed before you realise it.
Taking the sample
During the amniocentesis the consultant will pass a fine needle through your tummy into the amniotic fluid inside your pregnancy sac. Discomfort is minimal so no anaesthetic is needed. The doctor will draw up a tiny amount of amniotic fluid into a syringe.
Although the procedure sounds frightening, in reality it is usually very straightforward and is performed under continuous ultrasound vision to avoid any threat to your baby.
Before the procedure we will need confirmation of your blood group, if you are Rhesus Negative we will need to give you an injection of Anti-D once the amniocentesis has been performed. This injection carries an additional charge.
If you wish, we can also perform a 100% accurate gender identification during the amniocentesis procedure. There is no additional charge for this service.
How is the sample analysed?
The fluid sample is sent to a highly specialised forensic genetics laboratory for analysis. The sample is analysed using a process known as polymerase chain reaction (PCR) to gain a preliminary result. It is then set up for karyotyping in a culture which usually produces an identical result to the initial PCR.
Getting the results
Preliminary results for Down’s Syndrome, Edward’s Syndrome and Patau Syndrome are available in 2-3 days with the culture results following in about two weeks. Results from a full analysis of other requested chromosomal anomalies can also take up to two weeks.
Most genetic testing produces a definite answer; however 1 in 1000 of cases the results may prove inconclusive so further consultation or testing may be required. This is ten times less likely with an amniocentesis than if a CVS were performed earlier in pregnancy.
Are there any risks?
There is a 0.5 - 1% risk of miscarriage associated with having an amniocentesis. This means that for every 200 amniocentesis procedures performed it is possible that 1 - 2 patients would miscarry and 199 - 198 would be expected to progress normally.
Our consultants successfully perform hundreds of amniocentesis procedures every year and their audited miscarriage rates are lower than the national average of 0.5%.
Because an amniocentesis is performed later in pregnancy when miscarriages are less likely to occur naturally the risk may be lower than if a CVS was performed in early pregnancy.
Looking for a risk-free alternative to an amniocentesis? Have you considered a Non-Invasive Prenatal Test?