Prenatal Genetic Diagnosis
Aubrey Milunsky MBBCh, MRCP, DCH1
1 Director, Genetics Division, Eunice Kennedy Shriver Center, Waltham, Massachusetts, and is a medical geneticist at the Massachusetts General Hospital and Harvard Medical School
The fundamental philosophy of prenatal genetic diagnosis is to enable prospective parents at risk to have children selectively, unaffected by a specific hereditary disorder.1 In practice, this new technology has allowed healthy children to be born to many couples who, without the reassurance that it is now possible to extend to them, would not have had any on any further children. Indeed, it is clear that the number of children born because of the opportunities provided by prenatal diagnosis exceeds the number of pregnancies terminated on account of fetal genetic disease.
Despite the availability of prenatal diagnosis for more than a decade, utilization has been slow. Even today, the vast majority of states provide studies for less than 10% of women aged 35 years or more. In Massachusetts, where strenuous efforts at professional and public education have been made, utilization in this age category is about 20%. In the United States, the remarkable tardiness in the application of this valuable technology may be related to earlier concerns about the risk and accuracy of second trimester amniocentesis. Today, however, the explanations are more likely to be a lack of awareness of the indications for prenatal genetic studies and antipathy to abortion. Virtually all states now have at least a single prenatal diagnostic facility or are able to use laboratories in an adjoining state.
