IVF EDD

lovesred9

When figuring out your EDD after IVF...is day of ER the day of "ovulation"?  This is what I thought... but I am confused after my appointment today with the RE.  I had my ER on 4/18....so I thought I would be 6w4d.  When my RE walked into the room today for my ultrasound he said "well you are about 5 1/2 -6 weeks so we probably won't see a heartbeat yet."  I asked him how that was figured and then he started rambling numbers about so and so days past transfer and so and so days past ER.  My husband and I were VERY confused and just let it go.  Then we had an ultrasound and there was a heartbeat of 120....so I am assuming he was just confused.  I was his first appointment and he wasn't there when we got there....so I am thinking he was running late and just glanced and maybe looked at our transfer date instead.  I know it isn't a big deal because it is only a 4 day difference but it is just bugging me!  How was your EDD figured out?  Thanks!