Invasive prenatal procedures: is 'backup' tissue sampling indicated?
Prenatal karyotyping was performed on 136 patients because of one or more abnormalities detected on ultrasound. A total of 188 specimens was obtained which included fetal blood, amniotic fluid and chorionic villus. In 52 patients a second or 'backup' sample was obtained and in 100% cytogenetic analysis was successful. In contrast, failure to obtain a result occurred in 4 (4.7%) of the remaining 84 patients where a second sample was not obtained. In the event of primary sample failure, backup sampling not only improves the karyotype yield, but obviates the need for a second pass procedure with its attendant risks.
Meagher
S
S
Department of Cytogenetics, Children's Hospital, King George V Hospital for Mothers and Babies, Camperdown, N.S.W., Australia.
Smith
A
A
Milligan
J
J
D000653:Amniotic Fluid / Q000166:cytology; D001773:Blood Cells / Q000648:ultrastructure; D002824:Chorionic Villi / Q000648:ultrastructure; D002869:Chromosome Aberrations / Q000175:diagnosis*; D025063:Chromosome Disorders; D002875:Chromosomes / Q000648:ultrastructure; D005260:Female; D006801:Humans; D007621:Karyotyping / Q000379:methods*; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods* / Q000592:standards; D016216:Ultrasonography, Prenatal