Hello balajiraj.alwarsamy. Thanks for visiting healthcaremagic.com. The scan that your doctor is advising is an extensive ultrasound of your fetus. The scan is called a growth scan and it usually gives lots of information about the fetus including but not limited to size, weight, age of the fetus by it s development, and gives a measurement of amniotic fluid levels. It also can show some signs of the developmental changes that are seen in down syndrome which include lowered ears, frontal bone prominence, and some others. This scan can also usually show you what sex your fetus is as well. I am not sure how much the scan costs but I hope that the information that I have given you above helps. Be well, Dr. Kimberly