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Prediction of pregnancy complications by first-trimester maternal serum PAPP-A and free beta-hCG and with second-trimester uterine artery Doppler.
Spencer K, Yu CK, Cowans NJ, Otigbah C, Nicolaides KH.
Prenat Diagn 2005;25:949-53. -
Gestational sac volume measured by three-dimensional ultrasound at 11 to 13 + 6 weeks of gestation: relation to chromosomal defects.
Falcon O, Wegrzyn P, Faro C, Peralta CF, Nicolaides KH.
Ultrasound Obstet Gynecol 2005;25:546-50.