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Screening for trisomy 13 by fetal nuchal translucency and maternal serum free beta hCG and PAPP-A at 10-14 weeks of gestation.
Spencer K, Ong C, Skentou H, Liao AW, Nicolaides KH.
Prenat Diagn 2000;20:411-6. -
First trimester maternal serum free beta human chorionic gonadotrophin and pregnancy associated plasma protein A as predictors of pregnancy complications.
Ong CY, Liao AW, Spencer K, Munim S, Nicolaides KH.
BJOG 2000;107:1265-70.