Answer:
Chorionic Villi Sampling is the best test to conduct on the fetus.. It involves taking the DNA of the fetus and checking for defect in the DNA for the disease
Factors to consider include Pregnancy earlier than seven weeks or later than 13 weeks
Position of the baby, placenta, amount of amniotic fluid, or mother's anatomy
Vaginal or cervical infection
Samples or that may contain maternal tissue.
Your gynecologist will be in a better position to tell you the factors and screen for the factors before the procedure