Went for 1st prenatal today. Told we were potentially having twins and sent for u/s to get more exact due date. At u/s center - we were told 1 baby is larger than the other. Both have irregular heartbeats, the larger at 119 and the smaller at 136. We were told there was 50% chance of losing smaller one, although there is a possibility of losing the larger as well. Has anyone had irregular heart beat this early? If so, did it resolve? What were you told about potential miscarriage? If we are able to bring both to term, will they necessarily have some kind of birth defect?