I had spotting this weekend, so my RE had me come back in for another beta this morning. @ 18 DPIUI = 1,096.5. Its a doubling time of 39 hrs which is great!! I was pretty sad this weekend because I was spotting so bad I wasn't sure if this would be it for us. But I'm trying to take comfort in some great numbers. First ultrasound is still on for Jun 14th when I will be exactly 6 weeks.