Alaina is pregnant and has undergone prenatal testing. the initial tests raised some red flags, and a subsequent dna test confirmed that the fetus does in fact have three copies of chromosome 21

Having three copies of chromosome 21 will cause down syndrome,also called trisomy-21.
Instead of having 46 chromossomes(23 from each parent), Alaina's baby will have 47chromosomes.

People with this disease have characteristic facial features, commonly they have heart abnormalities, intellectual disability and language difficulties.