Women randomized to the intervention group also had higher knowledge scores ( 9.4 vs 8.6 on a 15-point scale ; mean group difference , 0.82 [ 95 % CI , 0.34-1 .31 ] ) and were more likely to correctly estimate the amniocentesis-related miscarriage risk ( 73.8 % vs 59.0 % ; OR , 1.95 [ 95 % CI , 1.39-2 .75 ] ) and their estimated age-adjusted chance of carrying a fetus with trisomy 21 ( 58.7 % vs 46.1 % ; OR , 1.66 [ 95 % CI , 1.22-2 .28 ] ) .