The hcg level not doubling, etc the way it should doesn't necessarily mean that there is something wrong. The same thing happened to me. My doctor called me in 4 times in 2 weeks to recheck my hcg levels because they weren't increasing at the rate she expected. On my way to my 5th blood draw appointment, I called my doctor and expressed my concern that a 2 day gap wasn't really enough time to see a significant change in results. Instead of the blood draw, she decided to do an ultrasound to check and see whether or not the baby was growing properly. As she was starting to tell me that it was usually too early to see much, she stopped mid sentence and said, "there's the baby, and there is the heartbeat." So far everything has been fine since, and I am in my 13th week.I would be more concerned, however, if your doctor has actually told you that he/she is concerned about a tubal (ectopic) pregnancy. Your doctor should be able to search for an amniotic sac with an ultrasound and verify that the baby is growing where it should be. My first pregnancy was an ectopic (tubal), so when I discovered that I was pregnant with this child, my doctor was able to tell that it is in the correct place with an ultrasound. I was at 4 weeks at the time. Unfortunately, if your pregnancy is an ectopic, there is no way to save the pregnancy.