Fetal echo is another form of an ultrasound scan, usually done by cardiologists, to evaluate the baby's heart in detail. It is only done in specific conditions -e.g. if the pregnant woman is a diabetic or has congenital heart disease. You need to consult your doctor regarding the indication for this test in your case. You need to take 3 cups of milk at this stage of your pregnancy. You are also underweight, and you need to improve your diet.