-
Screening for trisomy 18 by fetal nuchal translucency and maternal serum free beta -hCG and PAPP-A at 10-14 weeks of gestation.
Tul N, Spencer K, Noble P, Chan C, Nicolaides K.
Prenat Diagn 1999;19:1035-42. -
Increased nuchal translucency in trisomy 13 fetuses at 10-14 weeks of gestation.
Snijders RJ, Sebire NJ, Nayar R, Souka A, Nicolaides KH.
Am J Med Genet 1999;86:205-7.