Understanding Slow Rising HCG Levels and Early Pregnancy Concerns

Question
i found out i was pregnant on june 29th after a year of trying. my last period was may 24th but i had extremely irregular cycles when i got pregnant. ok so on the 29th my hcg level was 49. i had a test exactly one week later and it was 623. i had another one 2 days later and it was 633. four days later i went to the doctor where he told me there was a 50% chance the pregnancy was ectopic and scheduled me for another blood test and an ultrasound. a few hours later he called me with the results and told me my hcg level was 760 there was nothing in my fallopion tubes and there was a sac in my uterus... and then he asked me when i wanted to come in to have it terminated!!!! something about that just sounds wrong. my instant gut feeling told me not to do that and i told i at least want another blood test first. now by my calculations of when I believe i concieved and the size of the sac i would be between 4-5 weeks and from i've read my hcg level isn't that bad from where it should be. what do you think about this? in my opinion the doctor i have is a moron and a quack. if you can give me your opinion i would greatly appriciate it. thanks!

Answer
Dear Amber

The normal range for hCG blood levels is wide in normal pregnancy and cannot be used reliably to determine the status of pregnancy.

Vaginal ultrasound is more informative. If the ultrasound have shown an intrauterine sac without any evidence of life then i will repeat it in 2 weeks and make a decision accordingly. It seems to me that it might be posible that evidence of life in the sac could not be visualized as the pregnancy age was too early.