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Screening for trisomy 21 in twins using first trimester ultrasound and maternal serum biochemistry in a one-stop clinic: a review of three years experience.
Spencer K, Nicolaides KH.
BJOG 2003;110:276-80. -
Integrated ultrasound and biochemical screening for trisomy 21 using fetal nuchal translucency, absent fetal nasal bone, free beta-hCG and PAPP-A at 11 to 14 weeks.
Cicero S, Bindra R, Rembouskos G, Spencer K, Nicolaides KH.
Prenat Diagn 2003;23:306-10. -
First-trimester maternal serum PAPP-A, SP1 and M-CSF levels in normal and trisomic twin pregnancies.
Bersinger NA, Noble P, Nicolaides KH.
Prenat Diagn 2003;23:157-62.