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First-trimester markers of aneuploidy in women positive for HIV.
Savvidou M, Samuel I, Syngelaki A, Poulton M, Nicolaides K.
BJOG 2011;118:844-8. -
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.