The best time is around week 20 as at this point it is possible to get a full image of the baby. Also any anamolies which are spotted can be dealt with.

thank you for your valuable feedback Nidhika,Tanushree & Payal

anomaly scan must be done before 20 weeks. go get it done ASAP

the thing is that my gynecologist has given me appointment on 21st of this month...is it too late? actually I had an ultrasound scan during my 3rd month due to threatened abortion

it can be done. but ur gynec. will definitely suggest u at d right time. so dont worry