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Second-trimester levels of pregnancy-associated plasma protein-A and free beta-hCG in pregnancies with trisomy 13.
Spencer K, Crossley JA, Aitken DA, Nicolaides KH.
Prenat Diagn 2005;25:358-61. -
Increased nuchal translucency with normal karyotype.
Souka AP, Von Kaisenberg CS, Hyett JA, Sonek JD, Nicolaides KH.
Am J Obstet Gynecol 2005;192:1005-21.