Levels rising but not doubling


I had beta hcg done Monday and it was 322. 48 hours later it was 534. My dr does not seem concerned and said it came up 60% which is what he wants to see. It has me nervous though. Has anyone had this and have positive outcomes? I’ve had two miscarriages and am praying I don’t go through that again. With my daughter my hcg levels doubled and did not just go up.