-
A reassessment of biochemical marker distributions in trisomy 21-affected and unaffected twin pregnancies in the first trimester.
Madsen HN, Ball S, Wright D, Tørring N, Petersen OB, Nicolaides KH, Spencer K.
Ultrasound Obstet Gynecol 2011;37:38-47. -
Screening for trisomy 21 in twins using first trimester ultrasound and maternal serum biochemistry in a one-stop clinic: a review of three years experience.
Spencer K, Nicolaides KH.
BJOG 2003;110:276-80.