Double test is one of the routine screening tests, recommended for all pregnant women to screen for common chromosomal disorders in the fetus such as Down, Edwards and Patau syndromes.

Edward syndrome is a rare genetic disorder that affects babies. Children with Edward syndrome are unlikely to survive after birth and, if they are lucky enough to be born, will develop abnormally. It is the second most common syndrome, after Down syndrome, with a rate of 1/3,000 to 1/8,000 newborns affected.

Edwards syndrome is a rare genetic disorder in fetuses, caused by an extra copy of chromosome 18 in the genome. When children have this syndrome, they often have developmental delays and may have other serious birth defects.