Skip Navigation LinksHome Page    >    Medical Recommendation for Amniocentesis
Pregnancy links...
Health links...
Genetics links...
Medical links...
Autism links...
Other links...

Why is there no medical recommendation for amniocentesis in all cases?

Amniocentesis (and chorionic villus sampling) is undoubtedly the only test that can categorically rule out chromosomal disorders. However, it is neither medically indicated nor recommended that every pregnant woman should undergo amniocentesis - only those who are at high risk of having a specific problem that can be examined by this test. Why?

The reason lies in the fact that pregnancy involves many risks, a great number of which cannot be tested for and which therefore remain untested - this is a compromise that we must accept at the present time.

Every pregnancy carries a 3%-4% risk of serious problems that are either detected at birth or during the first year of life. These include mental retardation, autism (PDD ), metabolic disorders, deafness, muscular dystrophy, dwarfism, dystrophic diseases of the brain, etc. Even after obtaining normal results for ultrasonography and amniocentesis, the majority of these problems cannot be categorically ruled out. A small number of these conditions can be tested for by using special techniques - these are recommended for families in which such diseases are known to be present - i.e. families at high risk.

The cost of each test that can currently be performed is enormous, so that these tests are not recommended in all cases.

Because we currently have to compromise on a considerable percentage of genetic problems, the risk in some of these conditions that are not tested for routinely can, for instance, be 1:2000 (i.e. out of 2000 mothers with similar characteristics undergoing amniocentesis, only one will be found with this syndrome).

Similarly, there are no medical grounds for checking specifically for Down syndrome or trisomy 18 if the risk is 1:2000.

Of course, financial cost-benefit calculations and the risk of miscarriage as a result of amniocentesis are taken into account.

The medical indications for undergoing amniocentesis are similar throughout the western world. Twenty years from now, it may well be possible to check for the entire spectrum of diseases with high reliability and at a relatively low price.

Notwithstanding this, the current feeling is that amniocentesis for chromosome analysis is important to the higher socioeconomic and non-religious classes in the western world. Twenty-four percent of all pregnancies in these classes undergo amniocentesis, and a large proportion of these are undertaken privately. The test also allows for the detection of less severe chromosomal problems (from the point of view of expression or their risk of mental retardation) than Down syndrome, such as sex chromosome disorders, translocations, and so on - the average risk for these problems in each pregnancy is 1:400. This risk further increases with maternal age, reaching 1:100 over the age of 35.
Haven't found what you're looking for? Search for it here:   
Comments (0)

Leave a Comment
Email (will not be published)
Website (optional)
Your Comment

Line and paragraph breaks are automatic. Some HTML allowed: <a href="" title="">, <b>, <i>, <strike>

Please type the characters you see in the picture:

All content Copyright © 2009-2011, Genetics of Pregnancy Encyclopedia Corporation. All rights reserved.