Edwards syndrome, also known as trisomy 18, is a chromosomal disorder caused by an extra chromosome 18. It is a serious genetic condition that can cause a range of physical and developmental problems.
The condition can be detected as early as the first trimester during a routine ultrasound. However, the accuracy of this detection is low and may not always be reliable. A more accurate diagnosis of Edwards syndrome can be made through a blood test known as a maternal serum screening test, where a sample of the mother's blood is taken and tested for biomarkers that indicate a higher risk of chromosomal abnormalities, including Edwards syndrome. If the test is positive, a diagnostic amniocentesis can be performed to confirm the diagnosis.
In some cases, Edwards syndrome may not be detected until after birth. The physical characteristics associated with the condition can be easily noticeable after birth, such as a small head, low-set ears, and clenched fists. If these characteristics are present, further testing may be needed to confirm the diagnosis.
Overall, Edwards syndrome can be detected as early as the first trimester through a maternal serum screening test or a diagnostic amniocentesis. However, in some cases, the condition may not be detected until after birth.