Hey hun i think the general rule is the more full your bladder the easier it is to see the baby, i drank half a bottle of a 1.5 Litre evian water and my bladder was pretty damn full haha. What happened whilst I was there was i had my scan, she done the NT scan check by checking the babys neck fold, i think this is a test for downs, i then had my blood pressure taken, provided my urine sample, had a chat with a doctor because my BMI is a little high *blush* and then had bloods taken for the downs test. I received my results in 2 days via the post. Hope this helps? xxx