Abstract: This invention represents a significant advance in prenatal diagnosis by providing urinary screening to detect fetal aneuploidies. Herein disclosed are methods for prenatally assessing risks of a pregnancy being affected by Down syndrome and other aneuploidies by testing maternal urine samples for levels of .beta.-core-hCG. Levels of maternal urinary .beta.-core-hCG above normal indicate a risk that the pregnancy is affected with Down syndrome, and in general risks of other fetal aneuploidies are indicated by either lower than normal or higher than normal maternal urinary .beta.-core-hCG levels. Assessments can be made based on urinary .beta.-core-hCG levels alone or in conjunction with levels of other urinary and/or serum markers, ultrasound parameters and other factors, such as, maternal age.