Waiting till its born is another idea. But most pregnant women want the potential father to be part of the pregnancy. Guys who just say that they don't either believe that it is there child or don't care in general are just plain dirtballs... (not saying you are youa tall) but I would start with the blood work. Go have her take new blood work and have them pinpoint the conception date for you guys and then work it out from there. If there are still questions talk it out, dont just leave her to make all the decisions. This is a hard time for you and for her. Hope all works out. If you need doctor information I would be glad to help out as I used to work for the hospital for a few years. Best of luck!