Hcg levels not doubling (21,000 to 26,000 72hrs) 5 weeks: miscarrying? Hello. Feeling very somber due to news received yesterday. My last date of period is May 20 2015. On June 22 2015 pregnancy was confirmed by blood test at walk-in clinic with an hcg level of 21,830. I mentioned I had some very minor brown spotting/discharge earlier that week so doctor ordered another blood test to confirm levels were still elevated (I did not endure any cramping during the spotting). I was called in to the clinic to be told that my hcg levels 3 days later on June 25 2015 had only elevated to 26,877. The doctor told me that because they are not doubling every 48-72 hours I should prepare for a miscarriage. I asked if I would know if I was miscarrying/should I be expecting to start bleeding and he said well you have been haven t you ... I was confused because it was extremely minuscule spotting, nothing like a period, and brown. I m going to see my GP on Monday and have my levels checked yet again to see if they re dropping or still not doubling. I ve been reading that with higher levels they can take longer to increase. Does anyone have any advice, or would be able to let me know what I should be looking for in a possible miscarriage? I also have an U/S July 10th as I have been told this is most accurate.