First-trimester growth restriction and fetal aneuploidy: the effect of type of aneuploidy and gestational age.

Objective: Our purpose was to determine the effect of type of aneuploidy and gestational age on first-trimester fetal growth.

Study Design: Crown-rump length measurement was obtained in pregnancies undergoing chorionic villus sampling in three large prenatal diagnosis centers. One hundred forty-four aneuploid fetuses, from 9 to 13 weeks' gestation, were compared with 440 matched control fetuses for evidence of crown-rump length shortening.