Prenatal diagnosis - advances bring new challenges
Article Abstract:
Current methods of prenatal diagnosis to detect genetic diseases include amniocentesis and chorionic villus sampling. In amniocentesis, a small sample of fluid surrounding the fetus is removed and tested for abnormalities. It is commonly performed at 16 weeks of pregnancy. This procedure has an increased risk of fetal loss of 0.5 percent and other complications are relatively rare. There has been an increase in the number of genetic diseases that can be diagnosed by this method. Performing tests during the later part of the pregnancy and the long wait for results are two disadvantages. Pregnancy terminations later in the pregnancy are riskier, and earlier testing with rapid results would ease medical and ethical concerns. Chorionic villus sampling shows promising results in overcoming these disadvantages. This procedure is done in the first three months of pregnancy, providing earlier and faster results. Although the safety and efficacy is improving, some defects may not appear in early prenatal diagnosis procedures. Future methods being investigated include: the isolation of maternal trophoblasts, part of the fetal embryo, found circulating in the blood; the use of DNA amplification of small amounts of fetal cells; and prenatal genetic testing done before implantation of fetuses with in vitro ("test tube") fertilization techniques.
Publication Name: The New England Journal of Medicine
Subject: Health
ISSN: 0028-4793
Year: 1989
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Prenatal diagnosis - when and how?
Article Abstract:
Women seek prenatal diagnosis primarily to determine if their fetus has Down's syndrome. Mothers under age 35 give birth to 80% of all children with Down's syndrome though nearly all genetic testing is performed for the 5% of mothers who are over age 35. Parents and physician need to know the risk to the fetus of amniocentesis or other invasive procedures and compare this risk to the risk of having a child with a genetic disorder, even though other screening techniques may indicate a normal child. Screening with maternal serum markers may help to identify women at greatest risk of carrying a Down's syndrome baby and eliminate reliance on age as the criterion for invasive procedures. Parents may use this information to decide to terminate a pregnancy or to prepare for problems which may begin with the child's arrival. They may want to meet other families with similar children or find physicians specializing in a particular disease.
Publication Name: The New England Journal of Medicine
Subject: Health
ISSN: 0028-4793
Year: 1992
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Screening for Down's syndrome -- too many choices?
Article Abstract:
Doctors should continue to use the second trimester blood test used to diagnose Down syndrome prenatally. A study published in 2003 introduced a new test that can be done in the first trimester. However, it depends on ultrasound measurements of the fetus, which are technically demanding.
Publication Name: The New England Journal of Medicine
Subject: Health
ISSN: 0028-4793
Year: 2003
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