Clinics can detect chromosomal abnormalities in embryos through a process called preimplantation genetic testing (PGT) or preimplantation genetic diagnosis (PGD). PGT involves testing cells from embryos created through in vitro fertilization (IVF) to identify genetic conditions, including chromosomal abnormalities.

Common tests used in detecting chromosomal abnormalities in embryos include:

1. PGT-A (formerly known as PGS): This test screens for aneuploidy, which is an abnormal number of chromosomes in an embryo. A healthy embryo should have 46 chromosomes (23 pairs), and aneuploidy can lead to conditions like Down syndrome.

2. PGT-M (formerly known as PGD): This test is used to detect specific genetic mutations or conditions in embryos. It is commonly used for couples who are carriers of genetic disorders and want to avoid passing them on to their children.

3. Karyotype analysis: This test involves examining the chromosomal composition of cells from an embryo. It can detect structural abnormalities in chromosomes that may not be identified through other tests.

4. FISH (Fluorescent In Situ Hybridization): This technique can detect specific chromosomal abnormalities by using fluorescent probes to bind to specific regions on the chromosomes.

5. CMA (Chromosomal Microarray Analysis): CMA is a high-resolution test that can identify both aneuploidies and submicroscopic chromosomal imbalances.