Is a miscarriage imminent if my hCG is not doubling?

Not necessarily. As with anything else in nature, there is a physiologic variation regarding the doubling time for beta HCG in the first trimester. The rule of thumb is that it should double every 48 hours if it is a viable intrauterine pregnancy. Failure to do so suggests blighted ovum/miscarriage, ectopic pregnancy, or even normal early pregnancy. See your gynecologist and get pelvic ultrasound to know for sure!
No. Serum HCG levels are expected to rise by 2/3 (not double) every 48 hours or so in the first 8 weeks of pregnancy. However all doctors have had a patient where the HCG rose , just not by that much and ended up in a normal pregnancy. An HCG level that doesn't rise at all or falls is much more concerning for miscarriage.

Related Questions

Had my IUI on 9/10 and got a bfp on 23/10. On 25/10 doctor has told me my hCG is not doubling! Is miscarriage inevitable? I'm going to test tomorrow

no. Sometime it takes longer than 48 hrs to double. Not knowing the exact numbers can not defiinitely tell. The next few days with the next quant will help determine. Read more...
good luck. The way to determine the answer is to keep your appointment and see if your HCG is rising or falling. Best of luck to you. Read more...

Hcg level went up after 3 weeks of miscarriage?

Possible Pregnancy. Whatever clots or specimen you had when you had the miscarriage should have been examined by the pathologist to determine the presence of embryonic or fetal parts because otherwise the HCG elevation means you still have the conceptus/embryonic/fetal parts inside you. Other possibility is a growing tumor that is secreting hcg. Read more...

Can one low hCG level reading determine a miscarriage??

Not really. One BHCG level really only confirms you are pregnant. It needs to be compared to subsequent levels and in the context of your clinical situation. How far along are you or should you be? Are you having bleeding and/or cramping etc. All these play into a possible diagnosis. Read more...