Prenatal screening during pregnancy may involve a variety of tests that your doctor may recommend to determine the likelihood of a baby being born with specific chromosomal abnormalities. A Dual Marker Test or Double Marker Test is one of them. During the first trimester of pregnancy, a doctor will typically recommend the Double marker test as part of routine prenatal care. A foetus may experience multiple difficulties due to genetic abnormalities that impact its development. These abnormalities may be caused by an imbalance in the number of chromosomes, structural defects in the chromosomes, or an excessive amount of genetic material found within a specific chromosome. These abnormalities can lead to chromosomal disorders, miscarriages, and congenital malformations. These kinds of fetal anomalies might result in postnatal malformations in the newborn if they are not discovered. The double marker or dual marker test is useful in identifying such anomalies.