Looks perfect to me. Double in 48 hours initially and then that rate slows to 72 hours, but its still doubled within 48 hours so try not to stress out. Perhaps you should stop having such regular blood tests now as it may be causing more stress than reassurance. And that's coming from having had a mc 6 months ago, I've only had two blood tests the first week then two more a week apart for my own reassurance this time. But I'm waiting for a scan to give me a definite answer - and it's just a matter of having patience unfortunately.