I've never been through this either but was any of the defects ever picked up on your 20 week scan? Maybe they'll let you have an anomaly scan a bit earlier so you don't have to wait so long to find out. If the doctor doesn't think there is any reason to be concerned then it's a good sign.
I can relate to the worry about there being a problem though and that feeling of "what if the doctors are wrong" because I had an anomaly picked up on my 20 week scan. Try to relax, put your trust in the doctors and enjoy your pregnancy and face that hurdle if you come to it. Easier said than done I know but otherwise you'll drive yourself crazy with worry and you've got many months of pregnancy left ahead of you.
