Fetal trisomy 18 risk:Likelihood:Pt:^Fetus:Qn:Based on maternal age
fetal trisomy 18 risk:likelihood:pt:^fetus:qn:based on maternal age
Fetal trisomy 18 risk:Likelihood:To identify measures at a point in time:^Fetus:Quantitative:Based on maternal age
fetal trisomy 18 risk:likelihood:to identify measures at a point in time:^fetus:quantitative:based on maternal age