Hi, i have just been for our first ultrasound at 7 weeks, 3 days to find out we are having twins. She sized baby a at 7 weeks with a heartrate of 140. Baby b however was a week behind and a heartrate of 117. She left it very much up in the air which leads me to think i should prepare myself that baby b might not be there on our next ultrasound? Has anyone any advice or experience with what is going on with me? Thanks guys!