Had hcg level tested 18 dpo was 1300 21 dpo was 3000 doctor said she expected to see it double every 72 hrs cos its was over 1300 but its doubling every 50 hrs can it indicate multiples is it high?

Possibly: Unfortunately, you will need further HCG level testing and a ultrasound later to determine a multiple gestation as it is too early at this time to predict.

Normal range: It sounds like your HCG is doubling appropriately. An ultrasound in the next two weeks will appropriately identify baby number and heartbeat if all is progressing well.