Hi We had twin pregnancy after ivf and in the 12 my scan everything seemed fine but we had to reduce 1 foetus due to some personal reason. In the 19th week now we had anomaly scan and quad marker test. Everything seems fine in the anamoly scan but the quad marker test is positive and says high risk for abdominal wall / neural tube defect. The AFP is 211 u/ml. (1) could it be due to reduced foetus in the womb which is still there and shrinking or is there a possibility of serious risk to other baby health. (2) what are our options now to confirm with accuracy the defect (if any) (3) what are the options if any abnormality is confirmed?