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Competing-risks model in screening for pre-eclampsia in twin pregnancy according to maternal factors and biomarkers at 11-13 weeks' gestation.
Francisco C, Wright D, Benkő Z, Syngelaki A, Nicolaides KH.
Ultrasound Obstet Gynecol 2017;50:589-595. pdf -
Screening for trisomy 21 in twin pregnancies in the first trimester: an update of the impact of chorionicity on maternal serum markers.
Spencer K, Kagan KO, Nicolaides KH.
Prenat Diagn 2008;28:49-52.