HCG not doubling

With history of recurrent loss we’re monitoring my HCG. I am on progesterone and aspirin. I have had three beta draws all two days apart and not a single one has doubled. Anyone have similar stories that have led to success or should I prepare for the worst??

6-29 (15DPO) 559

7-1 (17DPO) 904

7-3 (19DPO) 1225