What tests can uncover fetal abnormalities?

Several. Ultrasounds and invavise testing like amniocentesis or chorionic villus sampling.
Many. Fetal abnormalities can be seen w/ ultrasound, mother or fetal blood or amniotic fluid. We often need to know what we are looking for but screening tests can uncover a lot. Ultrasound often requires special skills to see abnormals. Amniocentesis is common and good for genetics. Now mother's blood screens for problems with hormone levels and fetal cells. More rarely, fetal blood necessary. Best.