32 MED. HUMANITIES 38 (June 2006).
The range of congenital conditions identifiable prenatally has expanded as tests have become more sophisticated. They include chromosomal disorders (such as Down's syndrome), single gene disorders (such as cystic fibrosis), and structural malformations. The last type of disorder is the most common and the least understood of genetic diseases and includes club foot, cleft lip, cleft palate, congenital heart defects, and neural tube defects. This list seems set to increase in the face of rapidly advancing technology.
In 1999, screening tests for Down's syndrome were offered to 70% of pregnant women who were identified as being at risk for fetal Down's syndrome in the UK. In 2001, this figure was 80% and the increased rates were generally high, although no official figures exist. The increase of screening looks set to increase even further. In a recent publication in the Lancet, Harris and colleagues concluded that "current guidelines should be changed to offer testing to all pregnant women, not just those whose risk of carrying an affected foetus exceeds a specific threshold." This sentiment has been echoed by the National Centre for Clinical Excellence (NICE) who, in their guidelines for the NHS on the care of pregnant women, recommended that all women should be offered a test for Down's syndrome, whatever their age. These trends are not just isolated to Down's syndrome. In a similar study it is asserted that screening all pregnant women for fragile X could be cost effective and the Advisory Committee on Genetic Testing (ACGT) has suggested that screening tests for all serious genetic conditions should be offered to all pregnant women.
According to current guidelines, those subsequently categorized as being at high risk of having a baby with a disability are offered diagnostic testing. This involves sampling fetal tissue for analysis in the laboratory using techniques such as amniocentesis, chorionic villus sampling (CVS), and fetal blood sampling. Although these tests may confirm a diagnosis they are not without risks, being associated with procedure related miscarriage rates of 0.5-1% for amniocentesis and 1-3% for CVS and fetal blood sampling. The study by Harris presents preference data from a sample of 534 sociodemographically diverse pregnant women in the San Francisco Bay area, for whom procedure related miscarriage was considered preferable to having a baby with chromosomal abnormalities and as a...