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Key Points
Prenatal diagnostic procedures allow prenatal detection of an ever-expanding list of fetal abnormalities by obtaining genetic, biochemical, and physiologic information about the fetus.
The specific procedure selected depends upon the gestational age and the information needed.
Genetic consultation should be available to help patients choose which diagnostic procedure is optimal for them.
Earlier prenatal diagnostic methods have become increasingly more common and are likely to increase in popularity. The most studied of these is CVS. Transcervical and transabdominal techniques are equally effective.
Early amniocentesis is not recommended now that compelling evidence regarding its disadvantages has been published.
Advances in molecular techniques have led to a declining number of reasons for using percutaneous umbilical blood sampling. It is now rarely the procedure chosen for determining fetal karyotype.
Percutaneous umbilical blood sampling is the most direct method of evaluating fetal anemia secondary to severe Rho(D) disease.
The majority of invasive diagnostic procedures are associated with low rates of complications commensurate with provider skill and experience.
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Amniocentesis was first used during the 1880s for decompression of polyhydramnios (Lambl, 1881). In 1930, placental localization was achieved after the intra-amniotic injection of contrast medium (Menees et al., 1930). Aburel (1937) described the termination of a pregnancy by the intra-amniotic injection of hypertonic saline. During the 1950s, the role of amniocentesis and measurement of bilirubin concentrations in monitoring rhesus disease was reported (Bevis, 1950; Walker, 1957).
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Amniocentesis for fetal chromosome analysis was also initiated in the 1950s. (Until 1956, the number of human chromosomes was not known.) The first reported application was for fetal sex determination (Fuchs and Riis, 1956). The feasibility of culturing and karyotyping amniotic fluid cells was demonstrated by Steele and Breg in 1966. The first prenatal diagnosis of an abnormal karyotype, a balanced translocation, was reported in 1967 by Jacobson and Barter. Trisomy 21 was detected prenatally by Valenti et al., in 1968. During the same year the first diagnosis of the metabolic disorder galactosemia was reported by Nadler (1968).
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Indications for amniocentesis include (1) increased risk for fetal aneuploidy, (2) increased risk for known fetal genetic or biochemical abnormalities, (3) increased risk for fetal open neural tube defect (ONTD), (4) evaluation for fetal infection, and (5) documentation of fetal lung maturity.
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In the United States, while it had been considered standard practice to offer genetic counseling and prenatal cytogenetic analysis to all women of advanced maternal age, (age 35 years or older at their expected date of delivery), these recommendations have changed. Most recent guidelines from the American College of Obstetricians and Gynecologists emphasize that all patients, regardless of age, should have the option for invasive prenatal cytogenetic analysis if they prefer (ACOG, 2007). It is no longer considered acceptable ...