This test looks for changes, or abnormalities, in the chromosomes that make up your body's DNA, or genetic road map. Abnormalities in your chromosomes help healthcare providers diagnose many medical conditions. In some cases, your chromosomes can help your healthcare provider predict a medical problem before you even have symptoms. Chromosome studies done on a developing baby inside a mother's womb can predict problems that a baby may be born with or develop later in life. It can help in the diagnosis of congenital chromosome abnormalities, including aneuploidy, structural abnormalities, and balanced rearrangements