Investigation of choice for diagnosing downs syndrome at 15 weeks of gestation in a mother with a history of delivering a down syndrome baby is which of the following:: (A) Triple screen test, (B) Amniocentesis, (C) Chorionic villous biopsy, (D) Ultrasonography
Answer is B. Amniocentesis is the investigation of choice for the diagnosis of downs syndrome. It is done between 14-16 weeks of gestation. It is performed in the context of prior history of a child with downs syndrome, advanced maternal age, abnormal triple or quad assay. Ref: Harrison's Principles of Internal Medicine, 17th Edition, Page 409 ; Textbook of Obstetrics By D.C.Dutta, 6th Edition, Page 107