An Amniocentesis test may be advised or requested by your physician if you are considered a ‘high-risk’ pregnancy, an older mother (usually over 35), or you have had a routine blood test come back that show abnormal levels of Alpha Fetoprotein (AFP) in your bloodstream.

Alpha Fetoprotein is a blood plasma protein which is produced by the fetal yolk sac and liver. High levels of this can suggest neural tube defects, such as Spina Bifida which involves the central nervous system, or low levels can be an indication of Down Syndrome symptoms where the baby has the incorrect number of chromosomes. The blood test alone is not used as diagnosis of any conditions and an abnormal reading does not necessarily mean that there is anything wrong with the fetus, it is simply an indicator that things may need to be investigated a little further for clarification.

The Amniocentesis test is not routinely carried out as part of your antenatal care but it is the most commonly used to test for chromosomal abnormalities and genetic birth defects. Deciding to have one is always a personal decision made by the mother and although the test is fairly straight forward and painless, there is still a certain amount of risk involved as there is a 1/200 chance that it may result in miscarriage, so you will need to make an informed decision on weighing up the risks/benefit factor.

The test is performed by your healthcare provider who will use an ultrasound to guide a thin needle in through your abdomen and withdraw a small amount of amniotic fluid. This fluid is then used as a confirmation diagnosis of any associated disorders your baby may have.

The risks of having a Down Syndrome child are mainly related to your age although women of any age can have a DS baby. It is not usually considered to be relative to the number of children you have had in the past, if you have a new partner or any medication you may have been on at the time of conception.

The statistics for having a Down Syndrome baby are as follows:

    • In your 20’s – You have a 1/1000 chance


    • In your 30’s – You have a 1/900. At 35, this increases to 1/400. At 37, it becomes 1/250


  • In your 40’s – You have a 1/100 chance and by the time you are 45 it has increased to 1/25.

Although it may seem a little bleak, the reality is that most women over 35 do go on to have safe and healthy pregnancies. It is vitally important as an older mother that you maintain a strict and healthy diet, refrain from any smoking or alcohol, have adequate levels of Folic Acid in your system (antenatal vitamins from around 12 weeks before conception – minimum of 400 micrograms per day is the recommended level), maintaining a healthy weight and continuous medical counselling. In fact, by following a healthy pregnancy plan at any age, you greatly reduce the above odds of having an abnormal pregnancy.